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321 results on '"H. U. Keller"'

1. Bilobate comet morphology and internal structure controlled by shear deformation

Author: Carsten Güttler, F. Preusker, Dennis Bodewits, Alice Lucchetti, Philippe Lamy, J.-B. Vincent, H. U. Keller, D. Nébouy, Björn Davidsson, A. T. Auger, Matteo Massironi, Stefano Debei, Cecilia Tubiana, F. La Forgia, Stubbe F. Hviid, Hans Rickman, M. De Cecco, Luca Penasa, M. A. Barucci, L. M. Lara, Nilda Oklay, C. Matonti, Nicholas Attree, J. L. Bertaux, Olivier Groussin, Sophie Viseur, Monica Lazzarin, Maurizio Pajola, Imre Toth, Francesco Marzari, Ivano Bertini, R. Rodrigo, Jakob Deller, Sylvain Bouley, Sonia Fornasier, Holger Sierks, V. Da Deppo, J. J. Lopez-Moreno, Wing-Huen Ip, Laurent Jorda, Giampiero Naletto, G. Cremonese, Frank Scholten, Marco Fulle, Xian Shi, Stefano Mottola, P. J. Gutierrez, Detlef Koschny, Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Faculty of Natural Sciences [Stirling], University of Stirling, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Geoscienze [Padova], Department of Physics and Astronomy [Uppsala], Uppsala University, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), national funding agency of Germany (DLR), national funding agency of France (CNES), national funding agency of Italy (ASI), national funding agency of Spain (MEC), national funding agency of Sweden (SNSB), ESA Technical Directorate, Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), European Space Agency (ESA)-European Space Agency (ESA), California Institute of Technology (CALTECH)-NASA, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), and Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: Solar System, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, 3d analysis, Comet, Geophysics, 010502 geochemistry & geophysics, 01 natural sciences, rosetta, Shear (geology), [SDU]Sciences of the Universe [physics], 13. Climate action, General Earth and Planetary Sciences, Sublimation (phase transition), Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Earth and Planetary Sciences (all), Geology, 0105 earth and related environmental sciences
Abstract: Bilobate comets—small icy bodies with two distinct lobes—are a common configuration among comets, but the factors shaping these bodies are largely unknown. Cometary nuclei, the solid centres of comets, erode by ice sublimation when they are sufficiently close to the Sun, but the importance of a comet’s internal structure on its erosion is unclear. Here we present three-dimensional analyses of images from the Rosetta mission to illuminate the process that shaped the Jupiter-family bilobate comet 67P/Churyumov–Gerasimenko over billions of years. We show that the comet’s surface and interior exhibit shear-fracture and fault networks, on spatial scales of tens to hundreds of metres. Fractures propagate up to 500 m below the surface through a mechanically homogeneous material. Through fracture network analysis and stress modelling, we show that shear deformation generates fracture networks that control mechanical surface erosion, particularly in the strongly marked neck trough of 67P/Churyumov–Gerasimenko, exposing its interior. We conclude that shear deformation shapes and structures the surface and interior of bilobate comets, particularly in the outer Solar System where water ice sublimation is negligible. The shape and internal structure of bilobate comet 67P is controlled by shear deformation inducing mechanically driven erosion along shear fracture networks, according to a 3D analysis of images from the Rosetta mission.
Published: 2019
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2. Long-term monitoring of comet 67P/Churyumov–Gerasimenko’s jets with OSIRIS onboard Rosetta

Author: Holger Sierks, Ekkehard Kührt, Philippe Lamy, L. M. Lara, Marco Fulle, M. De Cecco, Monica Lazzarin, H. U. Keller, A. Gicquel, M. I. Schmitt, Dennis Bodewits, Xian Shi, Jessica Agarwal, J. J. López-Moreno, Imre Toth, M. F. A'Hearn, Stefano Mottola, Olivier Groussin, Sonia Fornasier, R. Rodrigo, J. L. Bertaux, Frank Scholten, Cesare Barbieri, D. Prasanna, Jörg Knollenberg, Stefano Debei, Jakob Deller, Wing-Huen Ip, Stubbe F. Hviid, Carsten Güttler, Björn Davidsson, Cecilia Tubiana, Laurent Jorda, Nilda Oklay, Ivano Bertini, Michael Küppers, Detlef Koschny, Nicolas Thomas, G. Cremonese, Francesco Marzari, J.-B. Vincent, V. Da Deppo, Mohamed Ramy El-Maarry, Marc Hofmann, Maurizio Pajola, Hans Rickman, J.-R. Kramm, P. J. Gutierrez, M. A. Barucci, Giampiero Naletto, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Epoch (astronomy), Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Equinox, 01 natural sciences, Latitude, 0103 physical sciences, comets, Comets: individual: 67P/Churyumov, Gerasimenko, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Jet (fluid), biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Northern Hemisphere, Astronomy, Astronomy and Astrophysics, 620 Engineering, biology.organism_classification, 13. Climate action, Space and Planetary Science, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We used the OSIRIS camera system onboard the Rosetta spacecraft to monitor jet activity of comet 67P/Churyumov-Gerasimenko. With a monthly cadence, we covered an epoch from December 2014 to October 2015, thereby including the first equinox and the perihelion passage. Jet features were measured in individual images, which were used to perform a statistical inversion. The study provides maps for the locations of likeliest sources of jet activity on the comet’s surface as a function of time. The sources follow the sub-solar latitude, show clustering and a broadening of the activity band with time in the Northern hemisphere. On the Southern hemisphere they are not clustered but show a broader spread over all longitudes which is either related to the north-south dichotomy of the comet’s topography or due to a higher insolation during southern summer.
Published: 2017
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3. Modelling of the outburst on 2015 July 29 observed with OSIRIS cameras in the Southern hemisphere of comet 67P/Churyumov–Gerasimenko

Author: N. Oklay, Holger Sierks, Stefano Mottola, F. Preusker, Ivano Bertini, J.-R. Kramm, Géza Kovács, Jessica Agarwal, Michael Küppers, Nicolas Fougere, Giampiero Naletto, Matteo Massironi, F. Moreno, Mohamed Ramy El-Maarry, Hans Rickman, Sebastien Besse, Stephen C. Lowry, Stubbe F. Hviid, Monica Lazzarin, Xian Shi, L. M. Lara, A. Gicquel, Marco Fulle, S. Höfner, M. A. Barucci, J. B. Vincent, Jörg Knollenberg, M. F. A'Hearn, V. Da Deppo, Olivier Groussin, P. Gutiérrez-Marquez, Rafael Rodrigo, Francesco Marzari, Nafiseh Masoumzadeh, X. Hu, M. De Cecco, M. Rose, Ekkehard Kührt, Stefano Debei, Imre Toth, Cesare Barbieri, Björn Davidsson, Sonia Fornasier, Cecilia Tubiana, Jakob Deller, Gabriele Cremonese, Maurizio Pajola, Zhong-Yi Lin, F. Scholten, Wing-Huen Ip, Laurent Jorda, Detlef Koschny, Nicolas Thomas, P. J. Gutierrez, Marc Hofmann, Steve Boudreault, J. J. Lopez Moreno, Philippe Lamy, Dennis Bodewits, E. Frattin, Carsten Güttler, H. U. Keller, J. L. Bertaux, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, PI-DSMC software package, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Department of Climate and Space Sciences and Engineering (CLaSP), University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Research and Scientific Support Department, ESTEC (RSSD), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Mechatronics, Optics and Mechanical Engineering Informatics (MOMEI), Budapest University of Technology and Economics [Budapest] (BME), European Space Astronomy Centre (ESAC), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), ITA, USA, GBR, FRA, DEU, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, Infrared, Comet, Data analysis, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Methods: numerical, Methods: observational, 67P/Churyumov, Coma (optics), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, modelling, comet, Rosetta, 0103 physical sciences, Comets, High spatial resolution, Astrophysics::Solar and Stellar Astrophysics, OSIRIS, 010303 astronomy & astrophysics, Southern Hemisphere, Observations, Astrophysics::Galaxy Astrophysics, Gerasimenko, 0105 earth and related environmental sciences, Numerical, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [PHYS]Physics [physics], Physics, 67P, biology, 520 Astronomy, outburt, Astronomy, Astronomy and Astrophysics, Radius, 620 Engineering, biology.organism_classification, Outgassing, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Images of the nucleus and the coma (gas and dust) of comet 67P/Churyumov– Gerasimenko have been acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) cameras since 2014 March using both the wide-angle camera and the narrow-angle camera (NAC). We use images from the NAC camera to study a bright outburst observed in the Southern hemisphere on 2015 July 29. The high spatial resolution of the NAC is needed to localize the source point of the outburst on the surface of the nucleus. The heliocentric distance is 1.25 au and the spacecraft–comet distance is 186 km. Aiming to better understand the physics that led to the outgassing, we used the Direct Simulation Monte Carlo method to study the gas flow close to the nucleus and the dust trajectories. The goal is to understand the mechanisms producing the outburst. We reproduce the opening angle of the outburst in the model and constrain the outgassing ratio between the outburst source and the local region. The outburst is in fact a combination of both gas and dust, in which the active surface is approximately 10 times more active than the average rate found in the surrounding areas. We need a number of dust particles 7.83 × 1011 to 6.90 × 1015 (radius 1.97–185 μm), which correspond to a mass of dust (220–21) × 103 kg.
Published: 2017
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4. Close-up images of the final Philae landing site on comet 67P/Churyumov-Gerasimenko acquired by the ROLIS camera

Author: Jean-Pierre Bibring, Alexander Koncz, Katharina A. Otto, Ralf Jaumann, Stefano Mottola, B. Dolives, Gabriele Arnold, H. U. Keller, Harald Michaelis, Ivanka Pelivan, Stefan Schröder, H.-G. Grothues, F. Souvannavong, and Emile Remetean
Subjects: Asteroiden und Kometen, Brightness, 010504 meteorology & atmospheric sciences, Comet, FOS: Physical sciences, Image processing, Surface finish, 01 natural sciences, Photometry, Photometry (optics), Optics, 0103 physical sciences, Comets, 010303 astronomy & astrophysics, Image resolution, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Pixel, business.industry, Stray light, nucleus, Leitungsbereich PF, Astronomy and Astrophysics, Planetengeologie, Comet 67P/Churyumov-Gerasimenko, Space and Planetary Science, Planetare Sensorsysteme, business, Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: After coming to rest on the night side of comet 67P/Churyumov-Gerasimenko, the ROLIS camera on-board Rosetta’s Philae lander acquired five images of the surface below the lander, four of which were with the aid of LED illumination of different colors. The images confirm that Philae was perched on a sloped surface. A local horizon is visible in one corner of the image, beyond which we can see the coma. Having spent a full day on the surface Philae was commanded to lift and rotate, after which a final, sixth, LED image was acquired. The change in perspective allowed us to construct a shape model of the surface. The distance to the foreground was about 80 cm, much larger than the nominal 30 cm. This caused stray light, rather than directly reflected LED light, to dominate the image signal, complicating the analysis. The images show a lumpy surface with a roughness of apparently fractal nature. Its appearance is completely different from that of the first landing site, which was characterized by centimeter to meter-sized debris (Mottola et al., 2015). We recognize neither particles nor pores at the image resolution of 0.8 mm per pixel and large color variations are absent. The surface has a bi-modal brightness distribution that can be interpreted in terms of the degree of consolidation, a hypothesis that we support with experimental evidence. We propose the surface below the lander to consist of smooth, cracked plates with unconsolidated edges, similar to terrain seen in CIVA images.
Published: 2017
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5. Spectrophotometric variegation of the layering in comet 67P/Churyumov-Gerasimenko as seen by OSIRIS

Author: Cesare Barbieri, W-H. Ip, Pedro J. Gutiérrez, Jakob Deller, Björn Davidsson, D. Bodewits, Gloria Tognon, R. Rodrigo, F. La Forgia, V. Petropoulou, Philippe Lamy, Prasanna Deshapriya, H. U. Keller, Cecilia Tubiana, M. A. Barucci, Holger Sierks, V. Da Deppo, Carsten Güttler, Matteo Massironi, Marco Fulle, Imre Toth, Michel Franceschi, Sabrina Ferrari, Giampiero Naletto, Alice Lucchetti, Detlef Koschny, M. De Cecco, E. Frattin, Sonia Fornasier, J. J. Lopez-Moreno, Monica Lazzarin, Maurizio Pajola, Ivano Bertini, Luca Penasa, Luisa Lara, Francesca Ferri, Francesco Marzari, Pamela Cambianica, Jean-Loup Bertaux, Gabriele Cremonese, Stefano Debei, Xian Shi, Stefano Mottola, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics [Auburn], Auburn University (AU), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), NASA-California Institute of Technology (CALTECH), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Technische Universität Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Tognon, Gloria, Ferrari, S., Penasa, L., La Forgia, F., Massironi, M., Naletto, G., Lazzarin, M., Cambianica, P., Lucchetti, A., Pajola, M., Ferri, F., Güttler, C., Davidsson, B., Deshapriya, P., Fornasier, S., Mottola, S., Tóth, I., Sierks, H., Lamy, P. L., Rodrigo, R., Koschny, D., Barbieri, C., Barucci, M. A., Bertaux, J. -L., Bertini, I., Bodewits, D., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Deller, J., Franceschi, M., Frattin, E., Fulle, M., Gutiérrez, P. J., Ip, W. -H., Keller, H. U., Lara, L. M., López-Moreno, J. J., Marzari, F., Petropoulou, V., Shi, X., and Tubiana, C.
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Outcrop, Multispectral image, Narrow angle, Astrophysics, 01 natural sciences, WATER ICE, NUCLEUS, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, 0103 physical sciences, data analysis [methods], medicine, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Physics, Multispectral data, biology, general [Comets], Astronomy and Astrophysics, biology.organism_classification, Lobe, Comets: general, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], comets: general – comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis, Osiris, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Between August 2014 and September 2016, the ESA space mission Rosetta escorted comet 67P/Churyumov-Gerasimenko (67P) during its perihelion passage. The onboard OSIRIS Narrow Angle Camera (NAC) acquired high-resolution multispectral images of the cometary surface. These datasets allowed a characterization of the spectrophotometric variegation of the layering of the large lobe, correlated with the layer structural elevation. Aims. We perform a spectrophotometric characterization of the outcropping stratification of the small lobe of 67P as a function of its structural elevation, and consequently, a spectrophotometric comparison of the layered outcrops of the two lobes. Methods. We selected two sequences of post-perihelion OSIRIS NAC images (similar to 2.4 au outbound to the Sun), from which we built up two multispectral images, framing an extended geological section of the onion-like stratification of the small lobe. Then we classified the consolidated areas of the outcropping and the relative coarse deposits that were identified in the multispectral data with a two-class maximum likelihood method. For this, we defined the classes as a function of the structural elevation of the surface. Results. As a result, we identified a brightness variegation of the surface reflectance that is correlated with the structural elevation. The outer class, which is located at higher elevations, appears darker than the inner class. This fits previously obtained results for the large lobe. The reflectance values of the nucleus of 67P tend to decrease with increasing structural elevation. Conclusions. The observed spectrophotometric variegation can be due to a different texture as well as to a different content of volatiles and refractories. We suggest that the outer outcrops appear darker because they have been exposed longer, and the inner outcrops appear brighter because the surface has been more effectively rejuvenated. We interpret this variegation as the result of an evolutionary process.© ESO 2019, We are grateful to Andrea Longobardo for suggestions and corrections that improved our paper. OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS - University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2019
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6. Multidisciplinary analysis of the Hapi region located on Comet 67P/Churyumov–Gerasimenko

Author: Wing-Huen Ip, Philippe Lamy, Carsten Güttler, F. La Forgia, Nilda Oklay, R. Rodrigo, Z. Y. Lin, Dennis Bodewits, Stefano Debei, V. Da Deppo, H. U. Keller, Luca Penasa, Jakob Deller, Maurizio Pajola, Alice Lucchetti, Gabriele Cremonese, Giampiero Naletto, Sonia Fornasier, Detlef Koschny, Marco Fulle, P. J. Gutierrez, M. De Cecco, Holger Sierks, J. J. Lopez Moreno, Francesco Marzari, J.-C. Lee, Matteo Massironi, F. Preusker, Ivano Bertini, Stubbe F. Hviid, Sabrina Ferrari, Imre Tóth, Jessica Agarwal, Pamela Cambianica, Xian Shi, Frank Scholten, Lorenza Giacomini, Jean-Loup Bertaux, M. A. Barucci, Stefano Mottola, Luisa Lara, Björn Davidsson, M. R. El Maarry, Clement Feller, Cecilia Tubiana, Monica Lazzarin, Jean-Baptiste Vincent, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Geoscienze [Padova], Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Department of Physics [Auburn], Auburn University (AU), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, University of Trento [Trento], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], INAF - Osservatorio Astronomico di Trieste (OAT), Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université Libre de Bruxelles [Bruxelles] (ULB), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), European Space Agency, Swedish National Space Board, Ministerio de Educación y Ciencia (España), Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, German Centre for Air and Space Travel, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Pajola, M. [0000-0002-3144-1277], Penasa, L. [0000-0002-6394-3108], Fornasier, S. [0000-0001-7678-3310], Lucchetti, A. [0000-0001-7413-3058], Vicent, J. B. [0000-0001-6575-3079], Naletto, G. [0000-0003-2007-3138], Barucci, M. A. [0000-0002-1345-0890], Bertaux, J. L. [0000-0003-0333-229X], Deller, J. [0000-0001-8341-007X], Fulle, M. [0000-0001-8435-5287], Güttler, C. [0000-0003-4277-1738], Tubiana, C. [0000-0001-8475-9898], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH)-NASA, PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Université libre de Bruxelles (ULB), Agenzia Spaziale Italiana (ASI), Swedish National Space Agency (SNSA), Deutsches Zentrum für Luft- und Raumfahrt (DLR), and Centre National D'Etudes Spatiales (CNES)
Subjects: Asteroiden und Kometen, statistical [Methods], Comet, individual (67P C-G) [Comets], Comets: individual (67P C-G), Methods: data analysis, Methods: statistical, 01 natural sciences, Methods statistical, Gravitational potential, 0103 physical sciences, data analysis [Methods], 010303 astronomy & astrophysics, Southern Hemisphere, Physics, geography, geography.geographical_feature_category, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Multidisciplinary analysis, Planetengeodäsie, 67P/Churyumov–Gerasimenko Comets Rosetta Hapi, Northern Hemisphere, Astronomy, Astronomy and Astrophysics, methods: data analysis –methods: statistical – comets: individual (67P C-G), Space and Planetary Science, Ridge, individual: 67P C-G [Comets], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: By using the Rosetta/OSIRIS-NAC data set taken in 2014 August, we focus on the neck region, called Hapi, located on 67P Churyumov-Gerasimenko's Northern hemisphere. The gravitational potential and slopes of Hapi, coupled with the geological unit identification and the boulder size-frequency distributions, support the interpretation that both taluses and gravitational accumulation deposits observable on Hapi are the result of multiple cliff collapses that occurred at different times. By contrast, the fine-particle deposits observable in the central part of the study area are made of aggregates coming from the Southern hemisphere and deposited during each perihelion passage. Both the consolidated terrains on the western part of Hapi, as well as the centrally aligned ridge made of boulder-like features, suggest that Hapi is in structural continuity with the onion-like structure of the main lobe of 67P. Despite the dusty blanket observable on Hapi, its terrains are characterized by water-ice-rich components that, once repeatedly and rapidly illuminated, sublimate, hence resulting in the strong jet activity observed in 2014 August.© 2019 The Author(s)., The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2019
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7. High-temperature superconductors: underlying physics and applications

Author: Annette Bussmann-Holder and H. U. Keller
Subjects: 010302 applied physics, Superconductivity, Physics, Condensed Matter - Materials Science, High-temperature superconductivity, Condensed matter physics, Liquid helium, Condensed Matter - Superconductivity, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Chemistry, BCS theory, 01 natural sciences, law.invention, 00-02, Superconductivity (cond-mat.supr-con), law, Condensed Matter::Superconductivity, 0103 physical sciences, Fundamental physics, Cuprate, Microscopic theory, 010306 general physics
Abstract: Superconductivity was discovered in 1911 by Kamerlingh Onnes and Holst in mercury at the temperature of liquid helium (4.2 K). It took almost 50 years until in 1957 a microscopic theory of superconductivity, the so-called BCS theory, was developed. Since the discovery a number of superconducting materials were found with transition temperatures up to 23 K. A breakthrough in the field happened in 1986 when Bednorz and M\"uller discovered a new class of superconductors, the so-called cuprate high-temperature superconductors with transition temperatures as high as 135 K. This surprising discovery initiated new efforts with respect to fundamental physics, material science, and technological applications. In this brief review the basic physics of the conventional low-temperature superconductors as well as of the high-temperature superconductors are presented with a brief introduction to applications exemplified from high-power to low-power electronic devices. Finally, a short outlook and future challenges are presented, finished with possible imaginations for applications of room-temperature superconductivity., Comment: 13 pages, 15 figures
Published: 2019
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8. The backscattering ratio of comet 67P/Churyumov-Gerasimenko dust coma as seen by OSIRIS onboard Rosetta

Author: Pamela Cambianica, F. La Forgia, Jean-Loup Bertaux, P. J. Gutierrez, Alice Lucchetti, E. Frattin, Alessandra Rotundi, Detlef Koschny, Pedro Hasselmann, Xian Shi, Wing-Huen Ip, Giovanna Rinaldi, Philippe Lamy, Carsten Güttler, Giampiero Naletto, Stefano Mottola, Monica Lazzarin, Marco Fulle, J. J. Lopez Moreno, Sabrina Ferrari, Nafiseh Masoumzadeh, M. A. Barucci, H. U. Keller, D. Guirado, Imre Toth, V. Petropoulou, Gábor L. Kovács, Holger Sierks, Gabriele Cremonese, M. De Cecco, Cesare Barbieri, L. M. Lara, Björn Davidsson, Jakob Deller, Dennis Bodewits, S. Ivanovsky, Francesca Ferri, Cecilia Tubiana, Luca Penasa, Jessica Agarwal, Stefano Debei, Ivano Bertini, Maurizio Pajola, Olga Muñoz, Francesco Marzari, S. Fornasier, Matteo Massironi, F. Moreno, R. Rodrigo, V. Da Deppo, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Ministerio de Educación y Ciencia (España), Swedish National Space Agency, European Space Agency, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], INAF - Osservatorio Astronomico di Padova (OAPD), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Physics [Auburn], Auburn University (AU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Geoscienze [Padova], Fulle, M. [0000-0001-8435-5287], Tubiana, C. [0000-0001-8475-9898], Güttler, C. [0000-0003-4277-1738], Pajola, M. [0000-0002-3144-1277], Rinaldi, G. [0000-0002-2968-0455], Naletto, G. [0000-0003-2007-3138], Barucci, M. A. [0000-0002-1345-0890], Bertaux, J. L. [0000-0003-0333-229X], Deller, J. [0000-0001-8341-007X], Fornasier, S. [0000-0001-7678-3310], Penasa, L. [0000-0002-6394-3108], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA), and Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Subjects: 67P/Churyumov-Gerasimenko, Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, photometry, Comet, data analysis, scattering –methods: data analysis – techniques: image processing – techniques: photometric – comets: individual: 67P/Churyumov-Gerasimenko, techniques: image processing, Astrophysics, 01 natural sciences, Photometry (optics), Scattering, techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Churyumov–Gerasimenko, image processing [Techniques], data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], scattering, methods: data analysis, techniques: image processing, techniques: photometric, comets: individual: 67P/Churyumov-Gerasimenko, Phase angle, scattering, photometric [Techniques], comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, biology.organism_classification, methods: data analysis, image processing, 13. Climate action, Space and Planetary Science, Drag, Temporal resolution, Inverse scattering problem, Osiris, individual: 67P [Comets], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Remote sensing observations of dust particles ejected from comets provide important hints on the intimate nature of the materials composing these primitive objects. The measurement of dust coma backscattering ratio, BSR, defined as the ratio of the reflectance at phase angle 0 ◦ and 30 ◦ , helps tuning theoretical models aimed at solving the inverse scattering problem deriving information on the nature of the ejected particles. The Rosetta/OSIRIS camera sampled the coma phase function of comet 67P, with four series acquired at low phase angles from 2015 January to 2016 May. We also added previously published data to our analysis to increase the temporal resolution of our findings. We measured a BSR in the range ∼ [1.7-3.6], broader than the range found in literature from ground-based observations of other comets. We found that during the post-perihelion phase, the BSR is systematically larger than the classical cometary dust values only for nucleocentric distances smaller than ∼ 100 km. We explain this trend in terms of a cloud of chunks orbiting the nucleus at distances < 100 km ejected during perihelion and slowly collapsing on the nucleus over a few months because of the coma gas drag. This also implies that the threshold particle size for the dust phase function to become similar to the nucleus phase function is between 2.5 mm and 0.1 m, taking into account previous Rosetta findings. © 2018 The Author(s)., The support of the national funding agencies of Germany (DLR: Deutschen Zentrums fur Luft-und Raumfahrt), France (CNES: Centre national d' etudes spatiales), Italy (ASI: Agenzia Spaziale Italiana), Spain (MEC: Ministry of Education& Science), Sweden (SNSB: Swedish National Space Board), and the European Space Agency (ESA) Technical Directorate is gratefully acknowledged.
Published: 2019
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9. Diurnal variation of dust and gas production in comet 67P/Churyumov-Gerasimenko at the inbound equinox as seen by OSIRIS and VIRTIS-M on board Rosetta

Author: D. Bodewits, Lyn R. Doose, Giovanna Rinaldi, U. Fink, M. De Cecco, Ivano Bertini, Marco Fulle, Maria Teresa Capria, Anny Chantal Levasseur-Regourd, D. Bockelée-Morvan, Imre Toth, Luisa Lara, Sonia Fornasier, H. Krueger, Mauro Ciarniello, Vladimir E. Zakharov, Holger Sierks, Alessandra Migliorini, Gabriele Arnold, Andrea Longobardo, Carsten Güttler, X. Hu, Michelangelo Formisano, Francesco Marzari, Xian Shi, Wing-Huen Ip, Philippe Lamy, F. La Forgia, Stefano Mottola, Gabriele Cremonese, Detlef Koschny, Zhong-Yi Lin, David Kappel, Raphael Marschall, Fredric W. Taylor, V. Da Deppo, S. Ivanovski, J. J. López-Moreno, Fabrizio Capaccioni, Gianrico Filacchione, H. U. Keller, Stéphane Erard, M. C. De Sanctis, Jean-Loup Bertaux, J. Deller, Pedro J. Gutiérrez, Stefano Debei, R. Rodrigo, Jacques Crovisier, Giampiero Naletto, Björn Davidsson, Cecilia Tubiana, M. A. Barucci, Colin Snodgrass, Monica Lazzarin, Ludmilla Kolokolova, Agenzia Spaziale Italiana, German Research Foundation, Centre National de la Recherche Scientifique (France), Ministerio de Economía y Competitividad (España), Government of Sweden, European Space Agency, l'Observatoire de Paris, Science and Technology Facilities Council (UK), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Institut für Geodäsie und Geoinformationstechnik, Technische Universität Berlin (TU), International Space Science Institute [Bern] (ISSI), INAF - Osservatorio Astronomico di Trieste (OAT), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Physik und Astrophysik [Potsdam], Universität Potsdam, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Universita degli studi di Napoli 'Parthenope' [Napoli], Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics [Oxford], University of Oxford [Oxford], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Technische Universität Berlin (TUB), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Comet, Comets, Data analysis, General, Individual, Methods, FOS: Physical sciences, Coma (optics), Spatial distribution, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Methods: data analysis, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, data analysis [methods], ddc:530, 010303 astronomy & astrophysics, Southern Hemisphere, Comet: individual: 67P/Churyumov-Gerasimenko, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Diurnal temperature variation, Leitungsbereich PF, comets: individual: 67P/Churyumov-Gerasimenko, Institut für Physik und Astronomie, general [Comets], Astronomy and Astrophysics, Comets: general, 13. Climate action, Space and Planetary Science, astro-ph.EP, Environmental science, Spatial variability, Longitude, Astrophysics - Earth and Planetary Astrophysics
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., On 27 April 2015, when comet 67P/Churyumov-Gerasimenko was at 1.76 au from the Sun and moving toward perihelion, the OSIRIS and VIRTIS-M instruments on board the Rosetta spacecraft simultaneously observed the evolving dust and gas coma during a complete rotation of the comet.© C. Tubiana et al. 2019, OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Daten-technik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. VIRTIS was built by a consortium, which includes Italy, France, and Germany, under the scientific responsibility of the Istituto di Astrofisica e Planetologia Spaziali of INAF, Italy, which also guides the scientific operations. The VIRTIS instrument development, led by the prime contractor Leonardo-Finmeccanica (Florence, Italy), has been funded and managed by ASI, with contributions from Observatoire de Meudon financed by CNES, and from DLR. We thank the Rosetta Science Ground Segment and the Rosetta Mission Operations Centre for their support throughout all the phases of the mission. The VIRTIS calibrated data will be available through the ESA's Planetary Science Archive Website (www.rssd.esa.int) and is available upon request until posted to the archive. We thank the following institutions and agencies for support of this work: Italian Space Agency (ASI, Italy) contract number I/024/12/1, Centre National d'Etudes Spatiales (CNES, France), DLR (Germany), NASA (USA) Rosetta Program, and Science and Technology Facilities Council (UK).
Published: 2019
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10. Quantitative analysis of isolated boulder fields on comet 67P/Churyumov-Gerasimenko

Author: Philippe Lamy, G. Cremonese, W.-H. Ip, Pamela Cambianica, Marco Fulle, Sabrina Ferrari, Dennis Bodewits, Matteo Massironi, Alice Lucchetti, Frank Scholten, Jean-Loup Bertaux, P. J. Gutierrez, F. La Forgia, Björn Davidsson, Francesco Marzari, Carsten Güttler, Z. Y. Lin, Jakob Deller, Cecilia Tubiana, Ivano Bertini, Detlef Koschny, M. De Cecco, Monica Lazzarin, M. A. Barucci, Holger Sierks, Emanuele Simioni, H. U. Keller, S. Fornasier, R. Rodrigo, Stefano Debei, L. M. Lara, V. Da Deppo, Xian Shi, Stefano Mottola, J.-B. Vincent, Giampiero Naletto, Luca Penasa, Maurizio Pajola, Imre Tóth, J. J. Lopez-Moreno, Cambianica, P. [https://orcid.org/0000-0002-8091-4915], European Space Agency (ESA), Centre National D'Etudes Spatiales (CNES), Agencia Estatal de Investigación (AEI), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Agenzia Spaziale Italiana (ASI), Swedish National Space Agency (SNSA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Geoscienze [Padova], Department of Physics [Auburn], Auburn University (AU), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comets, Data analysis, General, Individual, Methods, Population, Comet, Narrow angle, Geometry, Astrophysics, 01 natural sciences, Power law, Fractal, individual: 67P/Churyumov-Gerasimenko [Comets], Power index, 0103 physical sciences, education, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Comets: individual: 67P/Churyumov-Gerasimenko, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Comets], Astronomy and Astrophysics, methods: data analysis, Comets: general, Space and Planetary Science, Spatial ecology, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We provide a detailed quantitative analysis of isolated boulder fields situated in three different regions of comet 67P/Churyumov-Gerasimenko: Imhotep, Hapi, and Hatmehit. This is done to supply a useful method for analyzing the morphology of the boulders and to characterize the regions themselves. Methods. We used OSIRIS Narrow Angle Camera images with a spatial scale smaller than 2 mpx(-1) and analyzed the size-frequency distribution and the cumulative fractional area per boulder population. In addition, we correlated shape parameters, such as circularity and solidity, with both the spatial and the size-frequency distribution of the three populations. Results. We identified 11 811 boulders in the Imhotep, Hapi, and Hatmehit regions. We found that the Hatmehit and Imhotep areas show power indices in the range of -2.3/-2.7. These values could represent a transition between gravitational events caused by thermal weathering and sublimation, and material formed during collapses that has undergone sublimation. The Hapi area is characterized by a lower power index (-1.2/-1.7), suggesting that those boulders have a different origin. They can be the result of material formed during gravitational events and collapses that has undergone continuous fragmentation. We calculated the cumulative fractional area (CFA) in order to investigate how the area is covered by boulders as a function of their sizes. The Hatmehit and Imhotep regions show a CFA that is well fit by a power law. In contrast, the Hapi area does not show the same trend. We analyzed the fractal distributions, finding that the populations seem to be fractal at all dimensions, except for the Hapi distribution, which shows a possible fractal behavior for small dimensions only. Finally, the average values of the shape parameters reveal solid and roundish boulders in all populations we studied.© ESO 2019, OSIRIS was built by a consortium of the Max-Planck Institut fur Sonnensystemforschung, in Guttingen, Germany, CISAS University of Padova, Italy, the Laboratoire de Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC and ESTEC for their work in support of the Rosetta mission. We made use of Arcgis 10.3.1 software together with the Matlab, Java, and ImageJ software to perform our analysis. I thank Frederic Moisy for sharing the box-count work.
Published: 2019
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11. Rosetta/OSIRIS observations of the 67P nucleus during the April 2016 flyby: High-resolution spectrophotometry

Author: H. U. Keller, Alice Lucchetti, M. De Cecco, Giampiero Naletto, D. Bodewits, Monica Lazzarin, Francesco Marzari, R. Rodrigo, P. J. Gutiérrez, Maurizio Pajola, Sonia Fornasier, J. D. P. Deshapriya, Stefano Debei, F. La Forgia, A. Barucci, J. J. López-Moreno, V. Da Deppo, Frank Preusker, Wing-Huen Ip, Philippe Lamy, Matteo Massironi, C. Feller, Holger Sierks, Pedro Hasselmann, Gabriele Cremonese, Björn Davidsson, Cecilia Tubiana, Luisa Lara, B. Gaskell, Carsten Güttler, Frank Scholten, Ivano Bertini, Marco Fulle, Sabrina Ferrari, Xian Shi, Stefano Mottola, Jean-Loup Bertaux, Detlef Koschny, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Planetary Science Institute [Tucson] (PSI), Feller, C. [0000-0002-2941-3875], Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, techniques: image processing, Astrophysics, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Frost line, Spectrophotometry, Spectral slope, Methods, Churyumov–Gerasimenko, image processing [Techniques], space vehicles: instruments, data analysis [Methods], 010303 astronomy & astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Physics, [PHYS]Physics [physics], biology, medicine.diagnostic_test, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Resolution (electron density), Comets, Data analysis, Image processing, Individual, Instruments, Space vehicles, Techniques, individual: 67P [Comets], Comet, FOS: Physical sciences, Terrain, Context (language use), instruments [Space vehicles], 0103 physical sciences, medicine, 0105 earth and related environmental sciences, Planetengeodäsie, space vehicles – space vehicles: instruments – comets: individual: 67P/Churyumov–Gerasimenko – techniques: image processing – methods: data analysis, Astronomy and Astrophysics, biology.organism_classification, methods: data analysis, 13. Climate action, Space and Planetary Science, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: From August 2014 to September 2016, the Rosetta spacecraft followed comet 67P/Churyumov-Gerasimenko along its orbit. After the comet passed perihelion, Rosetta performed a flyby manoeuvre over the Imhotep-Khepry transition in April 2016. The OSIRIS/Narrow-Angle-Camera (NAC) acquired 112 observations with mainly three broadband filters (centered at 480, 649, and 743 nm) at a resolution of up to 0.53 m/px and for phase angles between 0.095 degrees and 62 degrees. Aims. We have investigated the morphological and spectrophotometrical properties of this area using the OSIRIS/NAC high-resolution observations. Methods. We assembled the observations into coregistered color cubes. Using a 3D shape model, we produced the illumination conditions and georeference for each observation. We mapped the observations of the transition to investigate its geomorphology. Observations were photometrically corrected using the Lommel-Seeliger disk law. Spectrophotometric analyses were performed on the coregistered color cubes. These data were used to estimate the local phase reddening. Results. The Imhotep-Khepry transition hosts numerous and varied types of terrains and features. We observe an association between a feature's nature, its reflectance, and its spectral slopes. Fine material deposits exhibit an average reflectance and spectral slope, while terrains with diamictons, consolidated material, degraded outcrops, or features such as somber boulders present a lower-than-average reflectance and higher-than-average spectral slope. Bright surfaces present here a spectral behavior consistent with terrains enriched in water-ice. We find a phase-reddening slope of 0.064 +/- 0.001%/100 nm/degrees at 2.7 au outbound, similar to the one obtained at 2.3 au inbound during the February 2015 flyby. Conclusions. Identified as the source region of multiple jets and a host of water-ice material, the Imhotep-Khepry transition appeared in April 2016, close to the frost line, to further harbor several potential locations with exposed water-ice material among its numerous different morphological terrain units.© ESO 2019, OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, Laboratoire d'Astrophysique de Marseille, France, Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, Universidad Politechnica de Madrid, Spain, Department of Physics and Astronomy of Uppsala University, Sweden, and Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by DLR, MPS, CNES, and ASI. The SPICE libraries and PDS resources are developed and maintained by NASA. The authors thank the referee and editors for their questions, remarks, and advices for the improvement of this article.
Published: 2019
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12. Phase-curve analysis of comet 67P/Churyumov-Gerasimenko at small phase angles

Author: D. Bodewits, Marco Fulle, Monica Lazzarin, Jakob Deller, Giampiero Naletto, V. Da Deppo, Nafiseh Masoumzadeh, Stefano Debei, Mohamed Ramy El-Maarry, Detlef Koschny, Björn Davidsson, H. U. Keller, Cecilia Tubiana, J. J. Lopez-Moreno, Imre Toth, W-H. Ip, M. A. Barucci, Pedro Hasselmann, Gabriele Cremonese, Ludmilla Kolokolova, Sonia Fornasier, Colin Snodgrass, M. De Cecco, Pedro J. Gutiérrez, Xian Shi, Carsten Güttler, Ivano Bertini, Francesco Marzari, L. M. Lara, Stefano Mottola, Holger Sierks, R. Rodrigo, P. L. Lamy, J. L. Bertaux, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Department of Earth and Planetary Sciences [UCL/Birkbeck], Birkbeck College [University of London], DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), IMPEC - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Auburn], Auburn University (AU), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), PLANETO - LATMOS, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), California Institute of Technology (CALTECH)-NASA, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), and Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
Subjects: Asteroiden und Kometen, Study phase, 010504 meteorology & atmospheric sciences, publications, bibliography, Comet, comets: general – comets: individual: 67P/Churyumov-Gerasimenko – techniques: photometric – techniques: image processing, Individual, Image processing, techniques: image processing, Coherent backscattering, Astrophysics, 7. Clean energy, 01 natural sciences, photometric [techniques], techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Comets, publications, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, image processing [techniques], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Phase angle, bibliography - techniques, general [Comets], bibliography, Astronomy and Astrophysics, Phase curve, 67P/Churyumov-Gerasimenko - publications, bibliography - techniques, General - comets, Photometric - techniques, Computational physics, Comets: general, Wavelength, Space and Planetary Science, Phase ratio, 67P/Churyumov-Gerasimenko - publications, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society., The Rosetta-OSIRIS images acquired at small phase angles in three wavelengths during the fly-by of the spacecraft on 9-10 April 2016 provided a unique opportunity to study the opposition effect on the surface of comet 67P/Churyumov-Gerasimenko (67P). Our goal is to study phase curves of the nucleus at small phase angles for a variety of surface structures to show the differences in their opposition effect and to determine which surface properties cause the differences.© N. Masoumzadeh et al. 2019, OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany; the CISAS University of Padova, Italy; the Laboratoire d'Astrophysique de Marseille, France; the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain; the Research and Scientific Support Department of the ESA, Noordwijk, Netherlands; the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain; the Universidad Politechnica de Madrid, Spain; the Department of Physics and Astronomy of Uppsala University, Sweden; and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Operations Centre and the Rosetta Mission Operations Centre for the successful rendezvous with comet 67P/Churyumov-Gerasimenko. This research has made use of the USGS Integrated Software for Imagers and Spectrometers (ISIS). We gratefully acknowledge the developers of SPICE and NAIF/PDS resources. This research has made use of the scientific software shapeViewer www.comet-toolbox.com.L.K.acknowledges a support from the NASA SSW grant 80NSSC17K0731.
Published: 2019
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13. Linking surface morphology, composition, and activity on the nucleus of 67P/Churyumov-Gerasimenko

Author: Jessica Agarwal, J. Deller, Pedro J. Gutiérrez, R. Rodrigo, Monica Lazzarin, Gabriele Cremonese, Holger Sierks, J. D. P. Deshapriya, Stefano Debei, D. Bodewits, Björn Davidsson, Cecilia Tubiana, Imre Toth, Pedro Hasselmann, Giampiero Naletto, Marco Fulle, Sabrina Ferrari, M. A. Barucci, Sonia Fornasier, Carsten Güttler, J. J. Lopez Moreno, Wing-Huen Ip, Philippe Lamy, Cesare Barbieri, Jean-Loup Bertaux, M. De Cecco, F. La Forgia, M. Küppers, Z. Y. Lin, Maurizio Pajola, M. L. Lara, Ivano Bertini, H. U. Keller, V. Da Deppo, Francesco Marzari, C. Feller, Van H. Hoang, Detlef Koschny, Xian Shi, Stefano Mottola, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institute of Physics [Hanoi], Vietnam Academy of Science and Technology (VAST), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, University of Trento [Trento], Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), European Space Agency (ESA), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], ITA, USA, GBR, FRA, DEU, Federal Ministry of Education and Research (Germany), Agence Nationale de la Recherche (France), Agenzia Spaziale Italiana, Ministerio de Ciencia, Innovación y Universidades (España), and Government of Sweden
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet, observational [methods], Data analysis, FOS: Physical sciences, Coma (optics), Individual, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Photometric, 01 natural sciences, photometric [techniques], techniques: photometric, individual: 67P/Churyumov-Gerasimenko [Comets], Comet nucleus, 0103 physical sciences, medicine, data analysis [methods], Comets, Methods, 010303 astronomy & astrophysics, Observational, Optical depth, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Techniques, Resolution (electron density), Astronomy and Astrophysics, methods: data analysis, Plume, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, comets: individual: 67P/Churyumov-Gerasimenko – methods: data analysis – methods: observational – techniques: photometric, Radiance, Astrophysics::Earth and Planetary Astrophysics, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited., The Rosetta space probe accompanied comet 67P/Churyumov-Gerasimenko for more than two years, obtaining an unprecedented amount of unique data of the comet nucleus and inner coma. This has enabled us to study its activity almost continuously from 4 au inbound to 3.6 au outbound, including the perihelion passage at 1.24 au. This work focuses identifying the source regions of faint jets and outbursts and on studying the spectrophotometric properties of some outbursts. We use observations acquired with the OSIRIS/NAC camera during July-October 2015, that is, close to perihelion. Methods. We analyzed more than 2000 images from NAC color sequences acquired with 7-11 filters covering the 250-1000 nm wavelength range. The OSIRIS images were processed with the OSIRIS standard pipeline up to level 3, that is, converted in radiance factor, then corrected for the illumination conditions. For each color sequence, color cubes were produced by stacking registered and illumination-corrected images. Results. More than 200 jets of different intensities were identified directly on the nucleus. Some of the more intense outbursts appear spectrally bluer than the comet dark terrain in the visible-to-near-infrared region. We attribute this spectral behavior to icy grains mixed with the ejected dust. Some of the jets have an extremely short lifetime. They appear on the cometary surface during the color sequence observations, and vanish in less than some few minutes after reaching their peak. We also report a resolved dust plume observed in May 2016 at a resolution of 55 cm pixel(-1), which allowed us to estimate an optical depth of similar to 0.65 and an ejected mass of similar to 2200 kg, assuming a grain bulk density of similar to 800 kg m(-3). We present the results on the location, duration, and colors of active sources on the nucleus of 67P from the medium-resolution (i.e., 6-10 m pixel(-1)) images acquired close to perihelion passage. The observed jets are mainly located close to boundaries between different morphological regions. Some of these active areas were observed and investigated at higher resolution (up to a few decimeter per pixel) during the last months of operations of the Rosetta mission. Conclusions. These observations allow us to investigate the link between morphology, composition, and activity of cometary nuclei. Jets depart not only from cliffs, but also from smooth and dust-covered areas, from fractures, pits, or cavities that cast shadows and favor the recondensation of volatiles. This study shows that faint jets or outbursts continuously contribute to the cometary activity close to perihelion passage, and that these events are triggered by illumination conditions. Faint jets or outbursts are not associated with a particular terrain type or morphology.© S. Fornasier et al. 2019, OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Goettingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, the Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. S.F. acknowledges the financial support from the France Agence Nationale de la Recherche (programme Classy, ANR-17-CE31-0004). The authors thank H. Campins for his comments that helped us improve this article. The authors would like to thank Andrew Cooper and Marco Parigi for spotting the inconsistencies in regional boundaried of Fig. 1 in the online preprint version of the paper.
Published: 2019
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14. Multi-Band Superconductivity and the Steep Band -- Flat Band Scenario

Author: Annette Bussmann-Holder, Antonio Bianconi, H. U. Keller, and Arndt Simon
Subjects: High-temperature superconductivity, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, high temperature superconductivity, law.invention, Superconductivity (cond-mat.supr-con), isotope effects, law, Condensed Matter::Superconductivity, 0103 physical sciences, Kinetic isotope effect, Cuprate, 010306 general physics, Coupling, Physics, Superconductivity, Condensed Matter::Quantum Gases, polaron formation, Condensed matter physics, Condensed Matter - Superconductivity, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Multi band, multi-band superconductivity, Condensed Matter::Strongly Correlated Electrons, Flat band, 0210 nano-technology, Realization (systems)
Abstract: The basic features of multi-band superconductivity and its implications are derived. In particular, it is shown that enhancements of the superconducting transition temperature take place due to interband interactions. In addition, isotope effects differ substantially from the typical BCS scheme as soon as polaronic coupling effects are present. Special cases of the model are polaronic coupling in one band as realized e.g., in cuprates, coexistence of a flat band and a steep band like in MgB2, crossovers between extreme cases. The advantages of the multiband approach as compared to the single band BCS model are elucidated and its rather frequent realization in actual systems discussed, Comment: 16 pages, 9 figures
Published: 2019
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15. Comet 67P/Churyumov-Gerasimenko rotation changes derived from sublimation induced torques

Author: Tobias Kramer, Matthias Läuter, Stubbe F. Hviid, Laurent Jorda, H. U. Keller, Ekkehard Kührt, Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Insolation, Rotation period, Asteroiden und Kometen, Angular momentum, Inertial frame of reference, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, 01 natural sciences, methods: analytical, 0103 physical sciences, 67P/Churyumov-Gerasimenko Comets Rosetta Rotation Activity, Torque, 010303 astronomy & astrophysics, Fourier series, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], comets: general, comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Computational physics, On board, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Sublimation (phase transition), Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: (Context) The change of the rotation period and the orientation of the rotation axis of comet 67P/Churyumov-Gerasimenko (67P/C-G) is deducible from images taken by the scientific imaging instruments on-board the Rosetta mission with high precision. Non gravitational forces are a natural explanation for these data. (Aims) We describe observed changes for the orientation of the rotation axis and the rotation period of 67P/C-G. For these changes we give an explanation based on a sublimation model with a best-fit for the surface active fraction (model P). Torque effects of periodically changing gas emissions on the surface are considered. (Methods) We solve the equation of state for the angular momentum in the inertial and the body-fixed frames and provide an analytic theory of the rotation changes in terms of Fourier coefficients, generally applicable to periodically forced rigid body dynamics. (Results) The torque induced changes of the rotation state constrain the physical properties of the surface, the sublimation rate and the local active fraction of the surface. (Conclusions) We determine a distribution of the local surface active fraction in agreement with the rotation properties, period and orientation, of 67P/C-G. The torque movement confirms that the sublimation increases faster than the insolation towards perihelion. The derived relatively uniform activity pattern is discussed in terms of related surface features., 11 pages
Published: 2018
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16. Loss of the Surface Layers of Comet Nuclei

Author: Nicolas Thomas, H. U. Keller, and C. Alexander
Subjects: Physics, Spacecraft, Thermal inertia, business.industry, Comet, Astronomy, Astronomy and Astrophysics, Surface finish, Astrophysics, law.invention, Outgassing, Orbiter, Planetary science, Thermal conductivity, Space and Planetary Science, law, Surface roughness, Sublimation (phase transition), business
Abstract: The Deep Impact observations of low thermal inertia for comet 9P/Tempel 1 are of profound importance for the observations to be made by the Rosetta spacecraft at comet 67P/Churyumov-Gerasimenko. While sub-surface sublimation is necessary to explain the observations, the depth at which this occurs is no more than 2–3 cm and possibly less. The low thermal conductivity when combined with local surface roughness (also observed with Deep Impact) implies that local variations in outgassing rates can be substantial. These variations are likely to be on scales smaller than the resolution limits of all experiments on the Rosetta orbiter. The observed physico-chemical inhomogeneity further suggests that the Rosetta lander will only provide a local snapshot of conditions in the nucleus layer.
Published: 2018
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17. Tensile strength of 67P/Churyumov–Gerasimenko nucleus material from overhangs

Author: N. Attree, O. Groussin, L. Jorda, D. Nébouy, N. Thomas, Y. Brouet, E. Kührt, F. Preusker, F. Scholten, J. Knollenberg, P. Hartogh, H. Sierks, C. Barbieri, P. Lamy, R. Rodrigo, D. Koschny, H. Rickman, H. U. Keller, M. F. A’Hearn, A.-T. Auger, M. A. Barucci, J.-L. Bertaux, I. Bertini, D. Bodewits, S. Boudreault, G. Cremonese, V. Da Deppo, B. Davidsson, S. Debei, M. De Cecco, J. Deller, and M. R. El
Published: 2018
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18. Dawn mission's search for satellites of Ceres: Intact protoplanets don't have satellites

Author: Andreas Nathues, Steven P. Joy, Christopher T. Russell, Uri Carsenty, Brian McLean, Paul Fieseler, Stefano Mottola, Max Mutchler, P. Gutierrez-Marques, Lucy A. McFadden, Mark V. Sykes, Marc D. Rayman, H. U. Keller, David R. Skillman, Jian-Yang Li, Carol A. Polanskey, Nargess Memarsadeghi, Carol A. Raymond, and Stefan Schröder
Subjects: 010504 meteorology & atmospheric sciences, Dwarf planet, Astronomy, Astronomy and Astrophysics, Radius, 01 natural sciences, Optical navigation, Dwarf planet Ceres Asteroids Satellites of asteroids Asteroid Ceres, Meteorite, Space and Planetary Science, Asteroid, Geometric albedo, 0103 physical sciences, Satellite, Protoplanet, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences
Abstract: Upon its approach to orbit the dwarf planet Ceres in early 2015, optical navigation and dedicated satellite search images were acquired with the Dawn mission's framing camera 2. A team of searchers individually processed and examined the images for evidence of objects moving with Ceres. Completeness of search with respect to the space searched was calculated as a function of distance to Ceres and found to be complete down to 15 Ceres radii (Ceres' mean radius is 470 km). Upper limits of detectable magnitude were determined for each observed set of images and an upper limit in size was calculated assuming for the putative objects, Ceres' geometric albedo of 0.11. Nothing was found associated with Ceres down to a radius of 12 m for the most sensitive search, and down to a radius of 323 m for the least sensitive search circumstances. Examination of the physical properties of the 41 largest and most massive main belt asteroids suggests that large asteroids without satellites are intact and their interiors have internal strength. This is consistent with results from the Dawn mission at both Vesta and Ceres. Ceres' volatile-rich composition also is a likely contributor to both the absence of satellites at Ceres and of Ceres meteorites at Earth. These results suggest that collisional disruption creating rubble pile structure is a necessary condition for formation of satellites around main belt asteroids.
Published: 2018
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19. Meter-scale thermal contraction crack polygons on the nucleus of comet 67P/Churyumov-Gerasimenko

Author: Cesare Barbieri, Jessica Agarwal, Monica Lazzarin, Ekkehard Kührt, J. J. Lopez Moreno, Pedro J. Gutiérrez, M. A. Barucci, Detlef Koschny, Björn Davidsson, Nicolas Thomas, Claire Capanna, Cecilia Tubiana, J.-R. Kramm, Simone Marchi, Michael Küppers, Harald Michalik, Antoine Pommerol, Antoine Séjourné, Marco Fulle, Matteo Massironi, Philippe Lamy, M. F. A'Hearn, Nilda Oklay, Robert Gaskell, Stubbe F. Hviid, S. Höfner, Francesco Marzari, Mohamed Ramy El-Maarry, Olivier Groussin, Sylvain Bouley, Sonia Fornasier, Holger Sierks, Stefano Debei, Jean-Loup Bertaux, L. Sabau, K. P. Wenzel, Hans Rickman, Giampiero Naletto, V. Da Deppo, Ivano Bertini, J. B. Vincent, Gabriele Cremonese, Rafael Rodrigo, Luisa Lara, M. De Cecco, Wing-Huen Ip, Laurent Jorda, A.-T. Auger, J. Knollenberg, H. U. Keller, Carsten Güttler, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Industrial Engineering [Padova], Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), INAF - Osservatorio Astronomico di Padova (OAPD), Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), Instituto Nacional de Técnica Aeroespacial (INTA), Research and Scientific Support Department, ESTEC (RSSD), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Universität Bern [Bern], PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Polska Akademia Nauk (PAN), Technische Universität Braunschweig [Braunschweig], PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), European Space Agency (ESA)-European Space Agency (ESA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, ITA, USA, GBR, FRA, DEU, and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Geometry, Trough (economics), 01 natural sciences, Nucleus, Latitude, Jupiter, Comets, Geological processes, 0103 physical sciences, Thermal, Thermal analysis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Astronomy and Astrophysics, Space and Planetary Science, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Atmospheric temperature range, 620 Engineering, Geology
Abstract: We report on the detection and characterization of more than 6300 polygons on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, using images acquired by the OSIRIS camera onboard Rosetta between August 2014 and March 2015. They are found in consolidated terrains and grouped in localized networks. They are present at all latitudes (from North to South) and longitudes (head, neck, and body), sometimes on pit walls or following lineaments. About 1.5% of the observed surface is covered by polygons. Polygons have an homogeneous size across the nucleus, with 90% of them in the size range 1 – 5 m and a mean size of 3.0 ± 1.4 m. They show different morphologies, depending on the width and depth of their trough. They are found in networks with 3- or 4-crack intersection nodes. The polygons observed on 67P are consistent with thermal contraction crack polygons formed by the diurnal or seasonal temperature variations in a hard (MPa) and consolidated sintered layer of water ice, located a few centimeters below the surface. Our thermal analysis shows an evolution of thermal contraction crack polygons according to the local thermal environment, with more evolved polygons (i.e. deeper and larger troughs) where the temperature and the diurnal and seasonal temperature range are the highest. Thermal contraction crack polygons are young surface morphologies that probably formed after the injection of 67P in the inner solar system, typically 100,000 years ago, and could be as young as a few orbital periods, following the decreasing of its perihelion distance in 1959 from 2.7 to 1.3 a.u. Meter scale thermal contraction crack polygons should be common features on the nucleus of Jupiter family comets.© 2017 Elsevier Inc., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik and Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2018
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20. The big lobe of 67P/Churyumov–Gerasimenko comet: morphological and spectrophotometric evidences of layering as from OSIRIS data

Author: P. J. Gutierrez, Xian Shi, Carsten Güttler, Pedro Hasselmann, J. J. López-Moreno, Matteo Massironi, Monica Lazzarin, Detlef Koschny, Stubbe F. Hviid, M. A. Barucci, Björn Davidsson, Cecilia Tubiana, Ivano Bertini, Pamela Cambianica, Nicolas Thomas, Michael Küppers, Francesca Ferri, Luca Penasa, Francesco Marzari, M. De Cecco, W-H. Ip, J. L. Bertaux, Marco Franceschi, Laurent Jorda, Holger Sierks, J.-B. Vincent, Olivier Groussin, E. Frattin, F. La Forgia, Stefano Debei, Philippe Lamy, Jakob Deller, Maurizio Pajola, Nilda Oklay, Giampiero Naletto, Ekkehard Kührt, Sonia Fornasier, L. M. Lara, V. Da Deppo, Marco Fulle, Jörg Knollenberg, Emanuele Simioni, Sabrina Ferrari, R. Rodrigo, Gabriele Cremonese, Alice Lucchetti, H. U. Keller, Dennis Bodewits, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Fundacion Galileo Galilei, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], Center for Space and Habitability (CSH), University of Bern, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Ferrari, Sabrina, Penasa, L., La Forgia, F., Massironi, M., Naletto, G., Lazzarin, M., Fornasier, S., Hasselmann, P. H., Lucchetti, A., Pajola, M., Ferri, F., Cambianica, Pamela, Oklay, N., Tubiana, C., Sierks, H., Lamy, P. L., Rodrigo, R., Koschny, D., Davidsson, B., Barucci, M. A., Bertaux, J. -L., Bertini, I., Bodewits, D., Cremonese, G., Da Deppo, V., Debei, S., De Cecco, M., Deller, J., Franceschi, M., Frattin, Elisa, Fulle, M., Groussin, O., Gutiérrez, P. J., Güttler, C., Hviid, S. F., Ip, W. -H., Jorda, L., Keller, H. U., Knollenberg, J., Kührt, E., Küppers, M., Lara, L. M., López-Moreno, J. J., Marzari, F., Shi, X., Simioni, E., Thomas, N., Vincent, J. -B., Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), NASA-California Institute of Technology (CALTECH), Universität Bern [Bern] (UNIBE), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Technische Universität Braunschweig [Braunschweig]
Subjects: 67P/Churyumov-Gerasimenko, Brightness, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Techniques: image processing, Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Multispectral image, Comet, Data analysis, Mineralogy, Spatial distribution, 01 natural sciences, Texture (geology), Image processing, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, medicine, Comets, image processing [Techniques], spectral variegation, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], biology, OSIRIS cameras, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, general [Comets], Astronomy and Astrophysic, biology.organism_classification, 620 Engineering, Lobe, data analysi [Methods], medicine.anatomical_structure, multiple-filters, Variegation (histology), Osiris
Abstract: Between 2014 and 2016, ESA's Rosetta OSIRIS cameras acquired multiple-filters images of the layered nucleus of comet 67P/Churyumov-Gerasimenko, ranging from ultraviolet to near-infrared wavelengths. No correlation between layers disposition and surface spectral variegation has been observed so far. This paper investigates possible spectral differences among decametre-thickness outcropping layers of the biggest lobe of the comet by means of OSIRIS image dataset. A two-classes maximum likelihood classification was applied on consolidated outcrops and relative deposits identified on post-perihelion multispectral images of the big lobe. We distinguished multispectral data on the basis of the structural elevation of the onion-shell Ellipsoidal Model of 67P. The spatial distribution of the two classes displays a clear dependence on the structural elevation, with the innermost class resulting over 50 per cent brighter than the outermost one. Consolidated cometarymaterials located at different structural levels are characterized by different brightness and revealed due to the selective removal of large volumes. This variegation can be attributed to a different texture of the outcrop surface and/or to a different content of refractory materials.© 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society., We are grateful to Paul Helfenstein for corrections that improved our paper. OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Goottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission.
Published: 2018
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21. Regional unit definition for the nucleus of comet 67P/Churyumov-Gerasimenko on the SHAP7 model

Author: Holger Sierks, J.-B. Vincent, F. Preusker, Giampiero Naletto, Francesco Marzari, Sonia Fornasier, Stubbe F. Hviid, M. A. Barucci, P. J. Gutierrez, Carsten Güttler, J. J. Lopez-Moreno, Jörg Knollenberg, Ivano Bertini, Stefano Debei, V. Da Deppo, P. L. Lamy, Frank Scholten, Detlef Koschny, Björn Davidsson, W-H. Ip, Marco Fulle, Nicolas Thomas, M. R. El Maarry, Cecilia Tubiana, Monica Lazzarin, Ekkehard Kührt, L. M. Lara, Raphael Marschall, J. L. Bertaux, H. U. Keller, Dennis Bodewits, R. Rodrigo, Laurent Jorda, G. Cremonese, M. De Cecco, P. Theologou, Olivier Groussin, ITA, USA, GBR, FRA, DEU, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), California Institute of Technology (CALTECH)-NASA, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Swiss National Science Foundation, European Commission, and State Secretariat for Education, Research and Innovation (Switzerland)
Subjects: 67P/Churyumov-Gerasimenko, Morphology, Surface (mathematics), 010504 meteorology & atmospheric sciences, Comet, Geometry, Surface finish, Table (information), 01 natural sciences, Nucleus, Computer graphics, Rosetta, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Subdivision, Astronomy and Astrophysics, Space and Planetary Science, business.industry, 520 Astronomy, 620 Engineering, medicine.anatomical_structure, es, [SDU]Sciences of the Universe [physics], business, Unit (ring theory), Geology
Abstract: Open Acces publication. This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed., The previously defined regions on the nucleus of comet 67P/Churyumov-Gerasimenko have been mapped back onto the 3D SHAP7 model of the nucleus (Preusker et al., 2017). The resulting regional definition is therefore self-consistent with boundaries that are well defined in 3 dimensions. The facets belonging to each region are provided as supplementary material. The shape model has then been used to assess inhomogeneity of nucleus surface morphology within individual regions. Several regions show diverse morphology. We propose sub-division of these regions into clearly identifiable units (sub-regions) and a comprehensive table is provided. The surface areas of each sub-region have been computed and statistics based on grouping of unit types are provided. The roughness of each region is also provided in a quantitative manner using a technique derived from computer graphics applications. The quantitative method supports the sub-region definition by showing that differences between sub-regions can be numerically justified.© 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2.
Published: 2018
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22. Coma morphology of comet 67P controlled by insolation over irregular nucleus

Author: Nilda Oklay, Jessica Agarwal, V. Da Deppo, M. De Cecco, Philippe Lamy, J.-B. Vincent, Laurent Jorda, G. Cremonese, X. Hu, Steve Boudreault, Carsten Güttler, M. A. Barucci, W-H. Ip, Marco Fulle, M. Rose, Imre Toth, Stefano Debei, Detlef Koschny, Sonia Fornasier, Ekkehard Kührt, Cesare Barbieri, L. M. Lara, Jakob Deller, P. J. Gutierrez, Francesco Marzari, Holger Sierks, Xian Shi, Jörg Knollenberg, Stefano Mottola, Maurizio Pajola, Géza Kovács, R. Rodrigo, Giampiero Naletto, J. J. López-Moreno, Olivier Groussin, J.-R. Kramm, Jean-Loup Bertaux, Dennis Bodewits, H. U. Keller, Ivano Bertini, Michael Küppers, Stubbe F. Hviid, Björn Davidsson, Cecilia Tubiana, Monica Lazzarin, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], PI-DSMC software package, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Dipartimento di Fisica [Politecnico Milano] (POLIMI), Politecnico di Milano [Milan] (POLIMI), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Agencia Estatal de Investigación (España), European Space Agency, Swedish National Space Agency, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Dipartimento di Fisica [Politecnico Milano], Technische Universität Braunschweig [Braunschweig], PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), and Dipartimento di Fisica [Milano]
Subjects: Brightness, 010504 meteorology & atmospheric sciences, Comet, structural complexity, Coma (optics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, cometary comae, dust jets, 0103 physical sciences, Rosetta, medicine, Sunrise, surface, Surface layer, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astronomy and Astrophysics, dust coma, Outgassing, medicine.anatomical_structure, 13. Climate action, Astrophysics::Earth and Planetary Astrophysics, business, Nucleus, Comet 67/P
Abstract: While the structural complexity of cometary comae is already recognizable from telescopic observations, the innermost region, within a few radii of the nucleus, was not resolved until spacecraft exploration became a reality. The dust coma displays jet-like features of enhanced brightness superposed on a diffuse background . Some features can be traced to specific areas on the nucleus, and result conceivably from locally enhanced outgassing and/or dust emission. However, diffuse or even uniform activity over topographic concavity can converge to produce jet-like features. Therefore, linking observed coma morphology to the distribution of activity on the nucleus is difficult. Here, we study the emergence of dust activity at sunrise on comet 67P/Churyumov-Gerasimenko using high-resolution, stereo images from the OSIRIS camera onboard the Rosetta spacecraft, where the sources and formation of the jet-like features are resolved. We perform numerical simulations to show that the ambient dust coma is driven by pervasive but non-uniform water outgassing from the homogeneous surface layer. Physical collimations of gas and dust flows occur at local maxima of insolation and also via topographic focusing. Coma structures are projected to exhibit jet-like features that vary with the perspective of the observer. For an irregular comet such as 67P/Churyumov-Gerasimenko, near-nucleus coma structures can be concealed in the shadow of the nucleus, which further complicates the picture.© 2018 The Author(s)., OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support Office of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2018
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23. The phase function and density of the dust observed at comet 67P/Churyumov-Gerasimenko

Author: P. J. Gutierrez, W-H. Ip, F. Moreno, Monica Lazzarin, F. La Forgia, Ivano Bertini, Xian Shi, V. Da Deppo, Cesare Barbieri, Stefano Mottola, Holger Sierks, Giampiero Naletto, Pasquale Palumbo, M. A. Barucci, Jakob Deller, Stavro Ivanovski, H. S. Hviid, J. Lasue, Giovanna Rinaldi, Marco Fulle, Michael Küppers, Philippe Lamy, Hans Rickman, Stefano Debei, Ekkehard Kührt, Alessandra Rotundi, Detlef Koschny, Nicolas Thomas, R. Rodrigo, M. De Cecco, J.-R. Kramm, Björn Davidsson, Cecilia Tubiana, Laurent Jorda, G. Cremonese, Carsten Güttler, J. L. Bertaux, Anny Chantal Levasseur-Regourd, M. L. Lara, Olivier Groussin, Sonia Fornasier, Jörg Knollenberg, V. Della Corte, J. J. López-Moreno, H. U. Keller, Francesco Marzari, Dennis Bodewits, Agenzia Spaziale Italiana, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA-California Institute of Technology (CALTECH), Universität Bern [Bern] (UNIBE), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Technische Universität Braunschweig [Braunschweig], INAF - Osservatorio Astronomico di Trieste ( OAT ), Istituto Nazionale di Astrofisica ( INAF ), Istituto di Astrofisica e Planetologia Spaziali ( IAPS ), Dipartimento di Scienze e Tecnologie [Napoli] ( DIST ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Centro de Astrobiologia [Madrid] ( CAB ), Instituto Nacional de Técnica Aeroespacial ( INTA ) -Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), International Space Science Institute ( ISSI ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Laboratory for Ultraviolet and X-ray Optical Research [Padova] ( LUXOR ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ) -Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), National Central University [Taiwan] ( NCU ), Space Science Institute [Macau] ( SSI ), Macau University of Science and Technology ( MUST ), Aix Marseille Université ( AMU ), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] ( IGEP ), and European Space Astronomy Center ( ESAC )
Subjects: 67P/Churyumov-Gerasimenko, Brightness, comets: individual: 67P/Churyumov- Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Dust particles, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, space vehicles, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, 01 natural sciences, Astronomi, astrofysik och kosmologi, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Astronomy, Astrophysics and Cosmology, Phase function, Astrophysics::Solar and Stellar Astrophysics, comets, Particle density, 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Physics, 520 Astronomy, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, general [Comets], Astronomy and Astrophysics, Space vehicles, 620 Engineering, Bulk density, space vehicles, comets: general, comets: individual: 67P/Churyumov- Gerasimenko, Density distribution, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], space vehicles, Astrophysics::Earth and Planetary Astrophysics, Mass fraction
Abstract: The OSIRIS camera onboard Rosetta measured the phase function of both the coma dust and the nucleus. The two functions have a very different slope versus the phase angle. Here, we show that the nucleus phase function should be adopted to convert the brightness to the size of dust particles larger than 2.5 mm only. This makes the dust bursts observed close to Rosetta by OSIRIS, occurring about every hour, consistent with the fragmentation on impact with Rosetta of parent particles, whose flux agrees with the dust flux observed by GIADA. OSIRIS also measured the antisunward acceleration of the fragments, thus providing the first direct measurement of the solar radiation force acting on the dust fragments and thus of their bulk density, excluding any measurable rocket effect by the ice sublimation from the dust. The obtained particle density distribution has a peak matching the bulk density of most COSIMA particles, and represents a subset of the density distribution measured by GIADA. This implies a bias in the elemental abundances measured by COSIMA, which thus are consistent with the 67P dust mass fractions inferred by GIADA, i.e. (38 ± 8) per cent of hydrocarbons versus the (62 ± 8) per cent of sulphides and silicates.© 2018 The Author(s).Published by Oxford University Press on behalf of the Royal Astronomical Society., We thank the anonymous referee for having significantly improved the paper; and the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. All GIADA data presented here are available on request before archiving in the PSA. This research was supported by the Italian Space Agency (ASI) within the ASI-INAF agreements I/032/05/0 and I/024/12/0.
Published: 2018
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24. Exposed bright features on the comet 67P/Churyumov-Gerasimenko: distribution and evolution

Author: J. L. Bertaux, L. Jorda, Carsten Güttler, Francesco Marzari, Monica Lazzarin, D. Bodewits, Holger Sierks, V. Da Deppo, Jörg Knollenberg, Nafiseh Masoumzadeh, Giampiero Naletto, Maurizio Pajola, H. U. Keller, Björn Davidsson, Ivano Bertini, Philippe Lamy, Steve Boudreault, O. Groussin, Detlef Koschny, Michael Küppers, Nicolas Thomas, Cecilia Tubiana, J. D. P. Deshapriya, Stefano Debei, M. De Cecco, J. J. Lopez Moreno, Sonia Fornasier, Xian Shi, J. B. Vincent, Stefano Mottola, Pedro J. Gutiérrez, L. M. Lara, Alice Lucchetti, M. A. Barucci, J. Rainer Kramm, R. Rodrigo, N. Oklay, Gabriele Cremonese, Stubbe F. Hviid, Pedro Hasselmann, H. V. Hoang, Marco Fulle, Hans Rickman, F. Preusker, W-H. Ip, Clement Feller, Ekkehard Kührt, Cesare Barbieri, Jakob Deller, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, NASA Ames Research Center (ARC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern], German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Ministerio de Educación y Ciencia (España), European Space Agency, Swedish National Space Board, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Technische Universität Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), Laboratoire d'études spatiales et d'instrumentation en astrophysique ( LESIA ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Max-Planck-Institut für Sonnensystemforschung ( MPS ), INAF - Osservatorio Astronomico di Padova ( OAPD ), Istituto Nazionale di Astrofisica ( INAF ), NASA Ames Research Center ( ARC ), Deutsches Zentrum für Luft- und Raumfahrt [Berlin] ( DLR ), Laboratoire Atmosphères, Milieux, Observations Spatiales ( LATMOS ), Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Versailles Saint-Quentin-en-Yvelines ( UVSQ ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Centro de Astrobiologia [Madrid] ( CAB ), Instituto Nacional de Técnica Aeroespacial ( INTA ) -Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), International Space Science Institute ( ISSI ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ), Space Research Centre [Warsaw] ( CBK ), Polska Akademia Nauk ( PAN ), Laboratory for Ultraviolet and X-ray Optical Research [Padova] ( LUXOR ), CNR Institute for Photonics and Nanotechnologies ( IFN ), Consiglio Nazionale delle Ricerche [Roma] ( CNR ) -Consiglio Nazionale delle Ricerche [Roma] ( CNR ), Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), INAF - Osservatorio Astronomico di Trieste ( OAT ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), National Central University [Taiwan] ( NCU ), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] ( IGEP ), European Space Astronomy Center ( ESAC ), and Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' ( CISAS )
Subjects: 010504 meteorology & atmospheric sciences, Comet, Data analysis, 67P/Churyumov–Gerasimenko, Context (language use), Astrophysics, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, 0103 physical sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Techniques: photometric, Photometric techniques, data analysis [Methods], 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], biology, photometric [Techniques], Astronomy, Astronomy and Astrophysics, Albedo, biology.organism_classification, Reflectivity, On board, 13. Climate action, Space and Planetary Science, Osiris
Abstract: Context. Since its arrival at the comet 67P/Churyumov-Gerasimenko in August 2014, the Rosetta spacecraft followed the comet as it went past the perihelion and beyond until September 2016. During this time there were many scientific instruments operating on board Rosetta to study the comet and its evolution in unprecedented detail. In this context, our study focusses on the distribution and evolution of exposed bright features that have been observed by OSIRIS, which is the scientific imaging instrument aboard Rosetta. Aims. We envisage investigating various morphologies of exposed bright features and the mechanisms that triggered their appearance. Methods. We co-registered multi-filter observations of OSIRIS images that are available in reflectance. The Lommel-Seeliger disk function was used to correct for the illumination conditions and the resulting colour cubes were used to perform spectrophotometric analyses on regions of interest. Results. We present a catalogue of 57 exposed bright features observed on the nucleus of the comet, all of which are attributed to the presence of HO ice on the comet. Furthermore, we categorise these patches under four different morphologies and present geometric albedos for each category. Conclusions. Although the nucleus of 67P/Churyumov-Gerasimenko appears to be dark in general, there are localised HO ice sources on the comet. Cometary activity escalates towards the perihelion passage and reveals such volatile ices. We propose that isolated HO ice patches found in smooth terrains in regions, such as Imhotep, Bes, and Hapi, result from frost as an aftermath of the cessation of the diurnal water cycle on the comet as it recedes from perihelion. Upon the comet's return to perihelion, such patches are revealed when sublimation-driven erosion removes the thin dust layers that got deposited earlier. More powerful activity sources such as cometary outbursts are capable of revealing much fresher, less contaminated HO ice that is preserved with consolidated cometary material, as observed on exposed patches resting on boulders. This is corroborated by our albedo calculations that attribute higher albedos for bright features with formations related to outbursts.© ESO 2018., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2018
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25. Tensile strength of 67P/Churyumov-Gerasimenko nucleus material from overhangs (Corrigendum)

Author: A. T. Auger, Stubbe F. Hviid, Michael Küppers, Imre Toth, Ekkehard Kührt, Sonia Fornasier, Björn Davidsson, Simone Marchi, F. Scholten, M. A. Barucci, Cecilia Tubiana, Jörg Knollenberg, R. Rodrigo, Yann Brouet, W-H. Ip, P. Lamy, Monica Lazzarin, Paul Hartogh, Nicholas Attree, D. Nébouy, Francesco Marzari, Steve Boudreault, Ivano Bertini, P. J. Gutierrez, Detlef Koschny, Mohamed Ramy El-Maarry, Marco Fulle, L. M. Lara, Hans Rickman, F. Preusker, Holger Sierks, Nicolas Thomas, V. Da Deppo, Stephen C. Lowry, Giampiero Naletto, Cesare Barbieri, Jakob Deller, Géza Kovács, N. Oklay, J. J. Lopez Moreno, Stefano Debei, J.-R. Kramm, Maurizio Pajola, M. F. A'Hearn, Olivier Groussin, J. L. Bertaux, Carsten Güttler, M. De Cecco, Laurent Jorda, Dennis Bodewits, G. Cremonese, Xian Shi, H. U. Keller, J. B. Vincent, Stefano Mottola, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), ESA Scientific Support Office, Agence Spatiale Européenne = European Space Agency (ESA), Department of Astronomy and Space Physics [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], Università degli Studi di Trento (UNITN), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Southwest Research Institute [Boulder] (SwRI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ITA, USA, GBR, FRA, and DEU
Subjects: Physics, 67P/Churyumov-Gerasimenko, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], comets: general, 520 Astronomy, Astronomy and Astrophysics, Astrophysics, 620 Engineering, Methods observational, medicine.anatomical_structure, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Ultimate tensile strength, comets: general / comets: individual: Churyumov-Gerasimenko / methods: observational / errata, medicine, comets, Composite material, methods: observational, Nucleus, addenda, comets: individual: Churyumov-Gerasimenko, errata, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018
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26. Models of Rosetta/OSIRIS 67P Dust Coma Phase Function

Author: Giovanna Rinaldi, Jean-Loup Bertaux, Carsten Güttler, Marco Fulle, Xian Shi, Giampiero Naletto, Jessica Agarwal, Stefano Mottola, Dominique Bockelée-Morvan, Olga Muñoz, Holger Sierks, F. Moreno, V. V. Zakharov, Francesco Marzari, M. De Cecco, V. Della Corte, Stavro Ivanovski, E. Frattin, Detlef Koschny, L. M. Lara, Björn Davidsson, Cecilia Tubiana, Wing-Huen Ip, Philippe Lamy, Ivano Bertini, S. Fornasier, H. U. Keller, Ludmilla Kolokolova, Monica Lazzarin, Gabriele Cremonese, J. J. López-Moreno, Alessandra Rotundi, Dennis Bodewits, Stefano Debei, Imre Tóth, D. Guirado, P. J. Gutierrez, Jakob Deller, Zhong-Yi Lin, M. A. Barucci, R. Rodrigo, V. Da Deppo, Polish Academy of Sciences, Ministerio de Economía y Competitividad (España), European Commission, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), National Central University [Taiwan] (NCU), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Department of Industrial Engineering [Padova], University of Trento [Trento], Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), IMPEC - LATMOS, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), and Technische Universität Braunschweig [Braunschweig]
Subjects: methods: numerical, minor planets, asteroids: individual (67P/Churyumov-Gerasimenko), Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Library science, FOS: Physical sciences, 7. Clean energy, 01 natural sciences, 0103 physical sciences, Phase function, asteroids: individual (67P/Churyumov-Gerasimenko), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, asteroids: individual (67P), Physics, Earth and Planetary Astrophysics (astro-ph.EP), Mission operations, numerical [Methods], biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], asteroids: individual (67P Churyumov–Gerasimenko), biology.organism_classification, individual (67P/Churyumov-Gerasimenko) [Minor planets,asteroids], minor planets, Astrophysics::Earth and Planetary Astrophysics, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Minor planets,asteroids: individual (67P/Churyumov-Gerasimenko), Astrophysics - Earth and Planetary Astrophysics
Abstract: The phase function of the dust coma of comet 67P has been determined from Rosetta/OSIRIS images. This function shows a deep minimum at phase angles near 100°, and a strong backscattering enhancement. These two properties cannot be reproduced by regular models of cometary dust, most of them based on wavelength-sized and randomly oriented aggregate particles. We show, however, that an ensemble of oriented elongated particles of a wide variety of aspect ratios, with radii r 10 μm, and whose long axes are perpendicular to the direction of the solar radiation, are capable of reproducing the observed phase function. These particles must be absorbing, with an imaginary part of the refractive index of about 0.1 to match the expected geometric albedo, and with porosity in the 60%-70% range.© 2018. The American Astronomical Society. All rights reserved.., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, in Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire dAstrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politecnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB; grant No. 74/10: 2), and the ESA Technical Directorate is gratefully acknowledged. H.R. was also supported by grant No. 2011/01/B/ST9/05442 of the Polish National Science Center. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC, and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. This work was supported by contracts AYA2015-67152-R and AYA2015-71975-REDT from the Spanish Ministerio de Economia y Competitividad.
Published: 2018
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27. Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS

Author: H. U. Keller, Carsten Güttler, M. A. Barucci, Ivano Bertini, A. T. Auger, Matteo Massironi, M. De Cecco, Simone Marchi, Stubbe F. Hviid, Raphael Marschall, Mohamed Ramy El-Maarry, Frank Scholten, Maurizio Pajola, Cesare Barbieri, Hans Rickman, R. Rodrigo, Jörg Knollenberg, Stefano Mottola, Jakob Deller, Marco Fulle, Michael Küppers, A. Gracia-Berná, Nilda Oklay, W-H. Ip, V. Da Deppo, P. J. Gutiérrez, Laurent Jorda, Holger Sierks, Sonia Fornasier, Jean-Loup Bertaux, J.-B. Vincent, Harald Michalik, Olivier Groussin, Antoine Pommerol, Marc Hofmann, Frank Preusker, Detlef Koschny, Nicolas Thomas, J.-R. Kramm, Monica Lazzarin, B. J. R. Davidsson, Philippe Lamy, Ekkehard Kührt, Cecilia Tubiana, L. M. Lara, Francesco Marzari, J. J. Lopez Moreno, Michael F. A'Hearn, Gabriele Cremonese, Stefano Debei, S. Höfner, Géza Kovács, and Giampiero Naletto
Subjects: Insolation, Physics, 010504 meteorology & atmospheric sciences, biology, Comet, Diurnal temperature variation, Weathering, Geophysics, biology.organism_classification, 01 natural sciences, Thermal contraction, Astrobiology, 13. Climate action, 0103 physical sciences, General Earth and Planetary Sciences, Osiris, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The OSIRIS experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov-Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here the first ever observations of meter-scale fractures on the surface of a comet. Some of these fractures form polygonal networks. We present an initial assessment of their morphology, topology, and regional distribution. Fractures are ubiquitous on the surface of the comet's nucleus. Furthermore, they occur in various settings and show different topologies suggesting numerous formation mechanisms, which include thermal insolation weathering, orbital-induced stresses, and possibly seasonal thermal contraction. However, we conclude that thermal insolation weathering is responsible for creating most of the observed fractures based on their morphology and setting in addition to thermal models that indicate diurnal temperature ranges exceeding 200 K and thermal gradients of ~15 K/min at perihelion are possible. Finally, we suggest that fractures could be a facilitator in surface evolution and long-term erosion.
Published: 2015
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28. A three-dimensional modelling of the layered structure of comet 67P/Churyumov-Gerasimenko

Author: Hans Rickman, Matteo Massironi, J.-R. Kramm, Ivano Bertini, Stubbe F. Hviid, Francesco Marzari, P. J. Gutierrez, M. De Cecco, Emanuele Simioni, Ekkehard Kührt, L. M. Lara, Frank Scholten, Detlef Koschny, Cesare Barbieri, Maurizio Pajola, R. Rodrigo, V. Da Deppo, Jakob Deller, Frank Preusker, S. Fornasier, Monica Lazzarin, Jean-Baptiste Vincent, Giampiero Naletto, Francesca Ferri, Robert Gaskell, Jessica Agarwal, Wing-Huen Ip, J-C. Lee, Laurent Jorda, N. Thomas, M. A. Barucci, Björn Davidsson, Michael Küppers, Alice Lucchetti, M. F. A'Hearn, Clement Feller, Marc Hofmann, Cecilia Tubiana, Olivier Groussin, Stefano Debei, Gabriele Cremonese, Holger Sierks, Marco Fulle, Philippe Lamy, Sabrina Ferrari, J. J. Lopez Moreno, F. La Forgia, Nilda Oklay, Carsten Güttler, E. Frattin, Luca Penasa, J. L. Bertaux, H. U. Keller, Jörg Knollenberg, Xian Shi, Stefano Mottola, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Astronomia [Padova], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), NASA Ames Research Center (ARC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Planetary Science Institute [Tucson] (PSI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Earth Sciences [Chung-Li City], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), DLR Institute of Planetary Research, German Aerospace Center (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Universita degli Studi di Padova-Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), and Universität Bern [Bern]
Subjects: 010504 meteorology & atmospheric sciences, Geometry, Concentric, Classification of discontinuities, 01 natural sciences, Layered structure, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Comets: general, Methods: data analysis, Physics, [PHYS]Physics [physics], comets: individual: 67P/Churyumov–Gerasimenko, comets: general, Astronomy and Astrophysics, Dimensional modeling, Ellipsoid, methods: data analysis, Lobe, medicine.anatomical_structure, Space and Planetary Science, Layering, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Free parameter
Abstract: International audience; We provide a three-dimensional model of the inner layered structure of comet 67P based on the hypothesis of an extended layering independently wrapping each lobe. A large set of terrace orientations was collected on the latest shape model and then used as a proxy for the local orientation of the surfaces of discontinuity which defines the layers. We modelled the terraces as a family of concentric ellipsoidal shells with fixed axis ratios, producing a model that is completely defined by just eight free parameters. Each lobe of 67P has been modelled independently, and the two sets of parameters have been estimated by means of non-linear optimization of the measured terrace orientations. The proposed model is able to predict the orientation of terraces, the elongation of cliffs, the linear traces observed in the Wosret and Hathor regions and the peculiar alignment of boulder-like features which has been observed in the Hapi region, which appears to be related to the inner layering of the big lobe. Our analysis allowed us to identify a plane of junction between the two lobes, further confirming the independent nature of the lobes. Our layering models differ from the best-fitting topographic ellipsoids of the surface, demonstrating that the terraces are aligned to an internal structure of discontinuities, which is unevenly exposed on the surface, suggesting a complex history of localized material removal from the nucleus.
Published: 2017
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29. Seasonal Mass Transfer on the Nucleus of Comet 67P/Chuyumov-Gerasimenko

Author: Frank Preusker, Wing-Huen Ip, Laurent Jorda, J. J. López-Moreno, Carsten Güttler, H. Rickman, Michael Küppers, Stubbe F. Hviid, Holger Sierks, Katharina A. Otto, G. Cremonese, M. A. Barucci, J. Deller, Ivano Bertini, Nilda Oklay, P. J. Gutierrez, Michael F. A'Hearn, Marc Hofmann, Nicolas Thomas, Frank Scholten, Jessica Agarwal, P. L. Lamy, Maurizio Pajola, V. Da Deppo, M. De Cecco, J.-R. Kramm, Cecilia Tubiana, Francesco Marzari, Imre Toth, Marco Fulle, Cesare Barbieri, Xian Shi, Stefano Mottola, Yuri V. Skorov, B. J. R. Davidsson, J. L. Bertaux, D. Koschny, Giampiero Naletto, Stefan Schröder, Monica Lazzarin, Dennis Bodewits, Jean-Baptiste Vincent, Sonia Fornasier, H. U. Keller, Jörg Knollenberg, Rafael Rodrigo, Ekkehard Kührt, L. M. Lara, Olivier Groussin, Stefano Debei, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Physics and Astronomy [Uppsala], Uppsala University, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), and ITA
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comets: individual (67P/Churyumov-Gerasimenko), Methods: data analysis, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Radiation, Granular material, 01 natural sciences, comet, Mass transfer, individual 67P/Churyumov-Gerasimenko, 0103 physical sciences, medicine, Comets, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Planetengeodäsie, Astronomy, Astronomy and Astrophysics, 620 Engineering, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, Sublimation (phase transition), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus, Water vapor, Astrophysics - Earth and Planetary Astrophysics
Abstract: We collect observational evidence that supports the scheme of mass transfer on the nucleus of comet 67P/Churyumov-Gerasimenko. The obliquity of the rotation axis of 67P causes strong seasonal variations. During perihelion the southern hemisphere is four times more active than the north. Northern territories are widely covered by granular material that indicates back fall originating from the active south. Decimetre sized chunks contain water ice and their trajectories are influenced by an anti-solar force instigated by sublimation. OSIRIS observations suggest that up to 20 % of the particles directly return to the nucleus surface taking several hours of travel time. The back fall covered northern areas are active if illuminated but produce mainly water vapour. The decimetre chunks from the nucleus surface are too small to contain more volatile compounds such as CO 2 or CO. This causes a north-south dichotomy of the composition measurements in the coma. Active particles are trapped in the gravitational minimum of Hapi during northern winter. They are "shock frozen" and only reactivated when the comet approaches the sun after its aphelion passage. The insolation of the big cavity is enhanced by self-heating, i. e. reflection and IR radiation from the walls. This, together with the pristinity of the active back fall, explains the early observed activity of the Hapi region. Sobek may be a role model for the consolidated bottom of Hapi. Mass transfer in the case of 67P strongly influences the evolution of the nucleus and the interpretation of coma measurements., Comment: 17 pages, 20 figures
Published: 2017
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30. Multivariate statistical analysis of OSIRIS/Rosetta spectrophotometric data of comet 67P/Churyumov-Gerasimenko

Author: J. Knollenberg, H. U. Keller, Francesco Marzari, M. De Cecco, M. Hofmann, Sonia Fornasier, Detlef Koschny, Olivier Groussin, Nicolas Thomas, Jean-Loup Bertaux, J. J. Lopez Moreno, D. Perna, M. Küppers, J. D. P. Deshapriya, Cesare Barbieri, Stefano Debei, Marcello Fulchignoni, Jakob Deller, Rafael Rodrigo, Philippe Lamy, Holger Sierks, Wing-Huen Ip, Giampiero Naletto, Laurent Jorda, C. Güttler, M. A. Barucci, Ivano Bertini, Gabriele Cremonese, Marco Fulle, Michael F. A'Hearn, Pedro Hasselmann, L. M. Lara, Monica Lazzarin, Clement Feller, Jean-Baptiste Vincent, E. Kührt, Björn Davidsson, Stubbe F. Hviid, Cecilia Tubiana, R. Kramm, Nilda Oklay, V. Da Deppo, Mohamed Ramy El-Maarry, Hans Rickman, Pedro J. Gutiérrez, National Aeronautics and Space Administration (US), Ministry of Science and Technology (Taiwan), ITA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institute of Planetary Research, German Aerospace Center (DLR), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), Agence Spatiale Européenne = European Space Agency (ESA), and California Institute of Technology (CALTECH)-NASA
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, Flux, Astrophysics, 01 natural sciences, 7. Clean energy, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, Comets: individual: 67P/Churyumov-Gerasimenko, Techniques: photometric, Rosetta, 0103 physical sciences, medicine, OSIRIS, data analysis [Methods], 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], photometric [Techniques], Northern Hemisphere, Astronomy, Astronomy and Astrophysics, biology.organism_classification, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, Homogeneous, Multivariate statistical, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus
Abstract: Full list of authors: Perna, D.; Fulchignoni, M.; Barucci, M. A.; Fornasier, S.; Feller, C.; Deshapriya, J. D. P.; Hasselmann, P. H.; Sierks, H.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; A'Hearn, M.; Bertaux, J. -L.; Bertini, I.; Cremonese, G.; Da Deppo, V.; Davidsson, B.; Debei, S. Deller, J.; De Cecco, M.; El-Maarry, M. R.; Fulle, M.; Groussin, O.; Gutierrez, P. J.; Güttler, C.; Hofmann, M.; Hviid, S. F.; Ip, W. -H.; Jorda, L.; Keller, H. U.; Knollenberg, J.; Kramm, R.; Kührt, E.; Küppers, M.; Lara, L. M.; Lazzarin, M.; Lopez Moreno, J. J.; Marzari, F.; Naletto, G.; Oklay, N.; Thomas, N.; Tubiana, C.; Vincent, J. -B., Context. The ESA Rosetta mission explored comet 67P/Churyumov-Gerasimenko in 2014-2016, following its target before and after the perihelion passage on 13 August 2015. The NAC camera of the OSIRIS imaging system allowed to map the nucleus surface acquiring images with different filters in the visible wavelength range. Aims. Here we study the spectrophotometric behaviour of the nucleus by a multivariate statistical analysis, aiming to distinguish homogeneous groups and to constrain the bulk composition. Methods. We applied the G-mode clustering algorithm to 16 OSIRIS data cubes acquired on 5-6 August 2014 (mostly covering the northern hemisphere) and 2 May 2015 (mostly covering the southern hemisphere), selected to have complete coverage of the comet's surface with similar observing conditions. Results. We found four similar homogeneous groups for each of the analysed cubes. The first group corresponds to the average spectrophotometric behaviour of the nucleus. The second (spectrally redder) and the third (spectrally bluer) groups are found in regions that were already found to deviate from the average terrain of the comet by previous studies. A fourth group (characterised by enhancements of the flux at 700-750 nm and 989 nm, possibly due to HO and/or NH emissions) seems connected with the cometary activity rather than with the bulk composition. Conclusions. While our aim in this work was to study the spectrophotometric behaviour of the nucleus of 67P/Churyumov-Gerasimenko as a whole, we found that a follow-up application of the G-mode to smaller regions of the surface could be useful in particular to identify and study the temporal evolution of ice patches, as well as to constrain the composition and physical processes behind the emission of dust jets. © ESO, 2017., OSIRIS was built by a consortium of the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentech-nik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. M.A. acknowledges NASA funding through Jet Propulsion Laboratory contract No. 1267923 and from the Akademie der Wissenschaften zu Gottingen. W.-H.Ip acknowledges the Ministry of Science and Technology, Taiwan (grant No. NSC 102-2112-M-008) and Macau University of Science and Technology (grant No. FDCT 017/2014/A1). We thank the ESA teams at European Space Astronomy Centre, European Space Operations Centre, and European Space Research and Technology Centre for their work in support of the Rosetta mission. Rosetta/OSIRIS data are available through the ESA's Planetary Science Archive (PSA, http://www.cosmos.esa.int/web/psa/rosetta).
Published: 2017
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31. The pristine interior of comet 67P revealed by the combined Aswan outburst and cliff collapse

Author: Frank Scholten, Frank Preusker, M. F. A'Hearn, Monica Lazzarin, Ekkehard Kührt, Harald Michalik, Olivier Groussin, Nilda Oklay, Jean-Baptiste Vincent, Luca Penasa, Detlef Koschny, M. De Cecco, Nicolas Thomas, Matteo Massironi, Imre Toth, V. Da Deppo, J. L. Bertaux, Laurent Jorda, Holger Sierks, Björn Davidsson, Carsten Güttler, Emanuele Simioni, Steve Boudreault, Stubbe F. Hviid, S. Höfner, Géza Kovács, Cecilia Tubiana, Sonia Fornasier, Marc Hofmann, Mohamed Ramy El-Maarry, Francesco Marzari, J.-R. Kramm, J. J. Lopez Moreno, Hans Rickman, Maurizio Pajola, Gabriele Cremonese, Giampiero Naletto, Sebastien Besse, M. A. Barucci, Pedro Hasselmann, Michael Küppers, Jörg Knollenberg, Luisa Lara, J. D. P. Deshapriya, Stefano Debei, Francesca Ferri, Rafael Rodrigo, Antoine Pommerol, Jessica Agarwal, H. U. Keller, Cesare Barbieri, Philippe Lamy, Jakob Deller, Zhong-Yi Lin, Stephen C. Lowry, P. J. Gutierrez, Ivano Bertini, W-H. Ip, Clement Feller, Emanuele Baratti, Marco Fulle, Sabrina Ferrari, Alice Lucchetti, Stefano Mottola, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Information Engineering [Padova] (DEI), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Industrial Engineering [Padova], University of Trento [Trento], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Department of Civil Chemical Environmental and Materials Engineering [Bologna] (DICAM), University of Bologna/Università di Bologna, Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA), European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], and University of Bologna
Subjects: outburst, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Escarpment, 01 natural sciences, Aswan, comet, Rosetta, 0103 physical sciences, Cliff, Table (landform), 010303 astronomy & astrophysics, QB, 0105 earth and related environmental sciences, Physics, geography, 67P, geography.geographical_feature_category, biology, cliff, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, Astronomy and Astrophysics, Crust, Landslide, Albedo, biology.organism_classification, collapse, WAC, 13. Climate action, Osiris, Comet 67/P
Abstract: International audience; Outbursts occur commonly on comets1 with different frequencies and scales2,3. Despite multiple observations suggesting various triggering processes4,5, the driving mechanism of such outbursts is still poorly understood. Landslides have been invoked6 to explain some outbursts on comet 103P/Hartley 2, although the process required a pre-existing dust layer on the verge of failure. The Rosetta mission observed several outbursts from its target comet 67P/Churyumov–Gerasimenko, which were attributed to dust generated by the crumbling of materials from collapsing cliffs7,8. However, none of the aforementioned works included definitive evidence that landslides occur on comets. Amongst the many features observed by Rosetta on the nucleus of the comet, one peculiar fracture, 70 m long and 1 m wide, was identified on images obtained in September 2014 at the edge of a cliff named Aswan9. On 10 July 2015, the Rosetta Navigation Camera captured a large plume of dust that could be traced back to an area encompassing the Aswan escarpment7. Five days later, the OSIRIS camera observed a fresh, sharp and bright edge on the Aswan cliff. Here we report the first unambiguous link between an outburst and a cliff collapse on a comet. We establish a new dust-plume formation mechanism that does not necessarily require the breakup of pressurized crust or the presence of supervolatile material, as suggested by previous studies7. Moreover, the collapse revealed the fresh icy interior of the comet, which is characterized by an albedo >0.4, and provided the opportunity to study how the crumbling wall settled down to form a new talus.The evolution of the collapse of the Aswan cliff9, observed by the OSIRIS Narrow Angle Camera (NAC)10 and the Rosetta Navigation camera (NavCam), is shown in Fig. 1. We estimated a total outburst ejected mass of cometary material between 0.5 × 106 and 1.0 × 106 kg for the 10 July event. By applying stereo-photogrammetric methods11 using multiple OSIRIS images (Supplementary Table 1), we determined the total volume of material that collapsed from the Aswan cliff. In Fig. 2, the dataset that depicts the aspect of the cliff before and after the collapse is presented. By using pre- and post-collapse three-dimensional (3D) models (see Methods), we have been able to measure the dimensions of the collapsed overhang (Supplementary Figs 1–2), deriving a total volume of 2.20 × 104 m3, with a 1σ uncertainty of 0.34 × 104 m3.
Published: 2017
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32. The reflectance spectrum of Titan's surface at the Huygens landing site determined by the Descent Imager/Spectral Radiometer

Author: Stefan Schröder and H. U. Keller
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Opposition surge, Radiometer, Haze, Spectrometer, Infrared, business.industry, FOS: Physical sciences, Astronomy and Astrophysics, Spectral line, symbols.namesake, Optics, Space and Planetary Science, symbols, Mixing ratio, Titan (rocket family), business, Geology, Remote sensing, Astrophysics - Earth and Planetary Astrophysics
Abstract: The Descent Imager/Spectral Radiometer aboard the Huygens probe successfully acquired images and spectra of the surface of Titan. To counter the effects of haze and atmospheric methane absorption it carried a Surface Science Lamp to illuminate the surface just before landing. We reconstruct the reflectance spectrum of the landing site in the 500-1500 nm range from Downward Looking Visual and Infrared Spectrometer data that show evidence of lamp light. Our reconstruction is a followup to the analysis by Tomasko et al. (2005), who scaled their result to the ratio of the up- and down flux measured just before landing. Instead, we use the lamp flux from the calibration experiment, and find a significantly higher overall reflectance. We attribute this to a phase angle dependance, possibly representing the opposition surge commonly encountered on solar system bodies. The reconstruction in the visible wavelength range is greatly improved. Here, the reflectance spectrum features a red slope, consistent with the presence of organic material. We confirm the blue slope in the near-IR, featureless apart from a single shallow absorption feature at 1500 nm. We agree with Tomasko et al. that the evidence for water ice is inconclusive. By modeling of absorption bands we find a methane mixing ratio of 4.5% +/- 0.5% just above the surface. There is no evidence for the presence of liquid methane, but the data do not rule out a wet soil at a depth of several centimeters., 23 pages, 15 figures
Published: 2017

33. Regional surface morphology of comet 67P/Churyumov-Gerasimenko from Rosetta/OSIRIS images: The southern hemisphere (Corrigendum)

Author: Monica Lazzarin, Laurent Jorda, J. B. Vincent, Cesare Barbieri, N. Thomas, Lorenza Giacomini, Olivier Groussin, S. Fornasier, Simone Marchi, B. J. R. Davidsson, A. Gracia-Berná, Antoine Pommerol, G. Cremonese, A. T. Auger, Raphael Marschall, Detlef Koschny, Matteo Massironi, P. J. Gutierrez, Stubbe F. Hviid, Holger Sierks, Cecilia Tubiana, Michael Küppers, F. Scholten, R. Rodrigo, Maurizio Pajola, N. Oklay, Mohamed Ramy El-Maarry, Ivano Bertini, J. J. Lopez Moreno, Géza Kovács, Hans Rickman, M. A. Barucci, W-H. Ip, J.-R. Kramm, Marco Fulle, P. L. Lamy, M. De Cecco, V. Da Deppo, Sebastien Besse, F. Preusker, Carsten Güttler, Giampiero Naletto, Francesco Marzari, H. U. Keller, M. F. A'Hearn, J. L. Bertaux, J.-C. Lee, Dennis Bodewits, Jörg Knollenberg, E. Kuehrt, L. M. Lara, Stefano Debei, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), NASA Ames Research Center (ARC), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), ESA Scientific Support Office, Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Università degli Studi di Trento (UNITN), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), Department of Information Engineering [Padova] (DEI), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Universität Bern [Bern], Universita degli Studi di Padova, European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universita degli Studi di Padova-Universita degli Studi di Padova, Max Planck Institute for Solar System Research (MPS), and California Institute of Technology (CALTECH)-NASA
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, 530 Physics, Comet, 01 natural sciences, Astrobiology, 0103 physical sciences, Rosetta, comets, OSIRIS, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, biology, 520 Astronomy, Planetengeodäsie, Astronomy, Astronomy and Astrophysics, 500 Science, biology.organism_classification, 620 Engineering, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience
Published: 2017
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34. Evidence for Surface Variegation in Rosetta OSIRIS Images of Asteroid 2867 Steins

Author: Holger Sierks, H. U. Keller, Stubbe F. Hviid, R. Kramm, P. J. Gutiérrez, Stefan Schröder, and W. Sabolo
Subjects: Point spread function, Earth and Planetary Astrophysics (astro-ph.EP), Pixel, biology, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, biology.organism_classification, Reflectivity, Photometry (optics), Impact crater, Space and Planetary Science, Asteroid, Color filter array, Osiris, Geology, Remote sensing, Astrophysics - Earth and Planetary Astrophysics
Abstract: The OSIRIS camera onboard Rosetta successfully acquired images of asteroid 2867 Steins through a variety of color filters during the flyby on 5 September 2008. The best images of this 5 km diameter asteroid have a resolution of 78 meters per pixel. We process the images by deconvolving with the point spread function and enlarging through the Mitchell-Netravali filter. The enhanced set is analyzed by means of various techniques (PCA, band ratios, stereo anaglyphs) to study surface morphology and search for variegation. We identify a landslide, which supports a YORP origin for Steins' unusual diamond shape. In addition, we find that the interior of one of two large craters on the south pole is bluer than the rest of the body., 17 pages, 9 figures
Published: 2017

35. Thermophysics of fractures on comet 67P/Churyumov-Gerasimenko

Author: H. U. Keller, D. Bodewits, Xian Shi, R. Moissl-Fraund, Monica Lazzarin, A.-T. Auger, Giampiero Naletto, M. A. Barucci, Jean-Loup Bertaux, Jean-Baptiste Vincent, Harald Michalik, Stefano Mottola, F. Moreno, F. La Forgia, Philippe Lamy, Jürgen Blum, Imre Toth, F. Preusker, Stubbe F. Hviid, Nilda Oklay, X. Hu, Gabriele Cremonese, Sonia Fornasier, M. De Cecco, P. Gutierrez-Marques, Holger Sierks, Wing-Huen Ip, Laurent Jorda, Marco Fulle, Ekkehard Kührt, Stefano Debei, V. Da Deppo, Pedro J. Gutiérrez, Björn Davidsson, Maurizio Pajola, J.-R. Kramm, Marc Hofmann, Cecilia Tubiana, Géza Kovács, F. Scholten, Rafael Rodrigo, A. Gicquel, Detlef Koschny, Nicolas Thomas, Olivier Groussin, Carsten Güttler, Michael Küppers, J. J. López-Moreno, Mohamed Ramy El-Maarry, S. Höfner, Hans Rickman, Cesare Barbieri, S. Zitzmann, Jakob Deller, Ivano Bertini, Michael F. A'Hearn, Francesco Marzari, J. Knollenberg, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Physics and Astronomy [Uppsala], Uppsala University, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Akademie der Wissenschaften zu Göttingen, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Mechatronics, Optics and Mechanical Engineering Informatics (MOMEI), Budapest University of Technology and Economics [Budapest] (BME), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Max-Planck-Institut für Sonnensystemforschung (MPS), Technische Universität Braunschweig [Braunschweig], Universität Bern [Bern], Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA)-European Space Agency (ESA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), European Space Agency (ESA), California Institute of Technology (CALTECH)-NASA, Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), and ITA
Subjects: Asteroiden und Kometen, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Radiation mechanisms: thermal, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Terrain, Astrophysics, Heat sink, 01 natural sciences, Mantle (geology), individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Radiative transfer, Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Comets, 67P/Churyumov-Gerasimenko, Radiation mechanisms: thermal, comets: general, Diurnal temperature variation, Planetengeodäsie, general [Comets], comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Mechanics, Outgassing, 13. Climate action, Space and Planetary Science, thermal [Radiation mechanisms], Thermophysics, Rosetta 67P Comets Thermal Fractures, Sublimation (phase transition)
Abstract: Full list of authors: Höfner, S.; Vincent, J. -B.; Blum, J.; Davidsson, B. J. R.; Sierks, H.; El-Maarry, M. R.; Deller, J.; Hofmann, M.; Hu, X.; Pajola, M.; Barbieri, C.; Lamy, P. L.; Rodrigo, R.; Koschny, D.; Rickman, H.; Keller, H. U.; A'Hearn, M. F.; Auger, A. -T.; Barucci, M. A.; Bertaux, J. -L. Bertini, I.; Bodewits, D.; Cremonese, G.; Da Deppo, V.; Debei, S.; De Cecco, M.; Fornasier, S.; Fulle, M.; Gicquel, A.; Groussin, O.; Gutiérrez, P. J.; Gutiérrez-Marqués, P.; Güttler, C.; Hviid, S. F.; Ip, W. -H.; Jorda, L.; Knollenberg, J.; Kovacs, G.; Kramm, J. -R.; Kührt, E.; Küppers, M.; La Forgia, F.; Lazzarin, M.; Lopez-Moreno, J. J.; Marzari, F.; Michalik, H.; Moissl-Fraund, R.; Moreno, F.; Mottola, S.; Naletto, G.; Oklay, N.; Preusker, F.; Scholten, F.; Shi, X.; Thomas, N.; Toth, I.; Tubiana, C.; Zitzmann, S., The camera OSIRIS on board Rosetta obtained high-resolution images of the nucleus of comet 67P/Churyumov-Gerasimenko (67P). Great parts of the nucleus surface are composed of fractured terrain. Aims. Fracture formation, evolution, and their potential relationship to physical processes that drive activity are not yet fully understood. Observed temperatures and gas production rates can be explained or interpreted with the presence of fractures by applying appropriate modelling methods. Methods. We followed a transient thermophysical model approach that includes radiative, conductive, and water-ice sublimation fluxes by considering a variety of heliocentric distances, illumination conditions, and thermophysical properties for a set of characteristic fracture geometries on the nucleus of 67P. We computed diurnal temperatures, heat fluxes, and outgassing behaviour in order to derive and distinguish the influence of the mentioned parameters on fractured terrain. Results. Our analysis confirms that fractures, as already indicated by former studies about concavities, deviate from flat-terrain topographies with equivalent properties, mostly through the effect of self-heating. Compared to flat terrain, illuminated cometary fractures are generally warmer, with smaller diurnal temperature fluctuations. Maximum sublimation rates reach higher peaks, and dust mantle quenching effects on sublimation rates are weaker. Consequently, the rough structure of the fractured terrain leads to significantly higher inferred surface thermal inertia values than for flat areas with identical physical properties, which might explain the range of measured thermal inertia on 67P. Conclusions. At 3.5 AU heliocentric distance, sublimation heat sinks in fractures converge to maximum values >50 W / m2 and trigger dust activity that can be related mainly to H2O. Fractures are likely to grow through the erosive interplay of alternating sublimation and thermal fatigue. © ESO, 2017., OSIRIS was built by a consortium led by the Max-Planck-Institut fur Sonnensystemforschung, Gottingen, Germany, in collaboration with CISAS, University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Scientific Support OCE of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politecnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut fur Datentechnik und Kommunikationsnetze der Technischen Universitat Braunschweig, Germany. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MINECO), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the Rosetta Science Ground Segment at ESAC, the Rosetta Mission Operations Centre at ESOC and the Rosetta Project at ESTEC for their outstanding work enabling the science return of the Rosetta Mission. The first author also wishes to thank the MPS for funding a research stipend, B. Gundlach for the helpful discussions of the application of his porous aggregate model, ITP Engines UK for providing a Ph.D. student research license of ESATAN-TMS (https://www.esatan-tms.com), which was used in this analysis, and the MPS Solar Orbiter Team for the funding of this licence. The authors gratefully acknowledge the referee work of Nalin Samarasinha, whose comments were very helpful in increasing the quality of this paper.
Published: 2017
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36. Planetary exploration with optical imaging systems review: What is the best sensor for future missions

Author: Demetrio Magrin, R. Bredthauer, H. U. Keller, Stefano Mottola, J. Janesick, Davide Greggio, Andrew D. Holland, N. Thomas, Ralf Jaumann, Thomas Behnke, Harald Michaelis, and Paul S. Smith
Subjects: Moons of Jupiter, Outer planets, Applied Mathematics, ComputerApplications_COMPUTERSINOTHERSYSTEMS, Mars Exploration Program, Condensed Matter Physics, GeneralLiterature_MISCELLANEOUS, Astrobiology, Geography, Optical imaging, Asteroid, Planet, Electronic, Optical and Magnetic Materials, Electrical and Electronic Engineering, Electronic, Optical and Magnetic Materials, Planetary exploration
Abstract: When we talk about planetary exploration missions most people think spontaneously about fascinating images from other planets or close-up pictures of small planetary bodies such as asteroids and comets. Such images come in most cases from VIS/NIR- imaging- systems, simply called ‘cameras’, which were typically built by institutes in collaboration with industry. Until now, they have nearly all been based on silicon CCD sensors, they have filter wheels and have often high power-consuming electronics. The question is, what are the challenges for future missions and what can be done to improve performance and scientific output. The exploration of Mars is ongoing. NASA and ESA are planning future missions to the outer planets like to the icy Jovian moons. Exploration of asteroids and comets are in focus of several recent and future missions. Furthermore, the detection and characterization of exo-planets will keep us busy for next generations. The paper is discussing the challenges and visions of imaging sensors for future planetary exploration missions. The focus of the talk is monolithic VIS/NIR- detectors.
Published: 2017

37. Cliffs versus Plains: Can ROSINA/COPS and OSIRIS data of comet 67P/Churyumov-Gerasimenko in autumn 2014 constrain inhomogeneous outgassing?

Author: Stefano Mottola, Yuri V. Skorov, Raphael Marschall, Frank Scholten, Jörg Knollenberg, Ekkehard Kührt, Nicolas Thomas, Martin Rubin, I. L. Lai, H. Sierks, Jong-Shinn Wu, Frank Preusker, Ying Liao, C. C. Su, Kathrin Altwegg, Wing-Huen Ip, Laurent Jorda, J.-B. Vincent, H. U. Keller, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Brightness, 010504 meteorology & atmospheric sciences, data Analysis, Mie scattering, Astrophysics, 01 natural sciences, law.invention, rosetta, modelling, Orbiter, law, 0103 physical sciences, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spectrometer, biology, Astronomy, Astronomy and Astrophysics, biology.organism_classification, Outgassing, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Sublimation (phase transition), Direct simulation Monte Carlo, Osiris
Abstract: International audience; Context. This paper describes the modelling of gas and dust data acquired in the period August to October 2014 from the European Space Agency's Rosetta spacecraft when it was in close proximity to the nucleus of comet 67P/Churyumov‐Gerasimenko. Aims. With our 3D gas and dust comae models this work attempts to test the hypothesis that cliff activity on comet 67P/Churyumov‐Gerasimenko can solely account for the local gas density data observed by the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) and the dust brightnesses seen by the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) in the considered time span. Methods. The model uses a previously developed shape model of the nucleus. From this, the water sublimation rates and gas temperatures at the surface are computed. The gas expansion is modelled with a 3D Direct Simulation Monte Carlo algorithm. A dust drag algorithm is then used to compute dust volume number densities in the coma, which are then converted to brightnesses using Mie theory and a line‐of‐sight integration. Furthermore we have studied the impact of topographic re‐radiation on the models. Results. We show that gas activity from only cliff areas produces a fit to the ROSINA/COPS data that is as statistically good as a purely insolation‐driven model. In contrast, pure cliff activity does not reproduce the dust brightness observed by OSIRIS and can thus be ruled out. On the other hand, gas activity from the Hapi region in addition to cliff activity produces a statistically better fit to the ROSINA/COPS data than purely insolation‐driven outgassing and also fits the OSIRIS observations rather well. We found that topographic re‐radiation does not contribute significantly to the sublimation behaviour of H2O but plays an important role in how the gas flux interacts with the irregular shape of the nucleus. Conclusions. We demonstrate that fits to the observations are non‐unique. We can conclude however that gas and dust activity from cliffs and the Hapi region are consistent with the ROSINA/COPS and OSIRIS data sets for the considered time span and are thus a plausible solution. Models with activity from low gravitational slopes alone provide a statistically inferior solution.
Published: 2017
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38. Characterization of dust aggregates in the vicinity of the Rosetta spacecraft

Author: Wing-Huen Ip, Carsten Güttler, Marco Fulle, Detlef Koschny, Nicolas Thomas, Laurent Jorda, Yuan Li, Nilda Oklay, H. U. Keller, J.-R. Kramm, J.-B. Vincent, Pedro Hasselmann, Cesare Barbieri, P. Gutiérrez Marqués, V. Da Deppo, Marc Hofmann, Sonia Fornasier, Ivano Bertini, Jakob Deller, Holger Sierks, P. J. Gutierrez, M. De Cecco, J. L. Bertaux, Michael Küppers, M. F. A'Hearn, Francesco Marzari, Olivier Groussin, Jörg Knollenberg, Björn Davidsson, Maurizio Pajola, J. J. López-Moreno, Jessica Agarwal, R. Rodrigo, Cecilia Tubiana, Theresa Ott, Bernhard Geiger, Stubbe F. Hviid, Géza Kovács, Monica Lazzarin, Giampiero Naletto, M. A. Barucci, Steve Boudreault, Dennis Bodewits, Esther Drolshagen, Xian Shi, Stefano Mottola, Ekkehard Kührt, L. M. Lara, Hans Rickman, Stefano Debei, Gabriele Cremonese, Philippe Lamy, Swedish National Space Board, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Centre National de la Recherche Scientifique (France), European Space Agency, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of Oldenburg, Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], NASA Ames Research Center (ARC), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung (MPS), Carl Von Ossietzky Universität Oldenburg, Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Image processing, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Comets: general, Comets: individual: 67P/ Churyumov-Gerasimenko, Astrobiology, Physics::Plasma Physics, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Rosetta, Comets, image processing [Techniques], OSIRIS, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Dynamic motion, Physics, [PHYS]Physics [physics], Comets: individual: 67P/Churyumov-Gerasimenko, biology, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, general [Comets], Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Characterization (materials science), Space and Planetary Science, Physics::Space Physics, Particle, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: In a Rosetta/OSIRIS imaging activity in 2015 June, we have observed the dynamic motion of particles close to the spacecraft. Due to the focal setting of the OSIRIS wide angle camera, these particles were blurred, which can be used to measure their distances to the spacecraft. We detected 109 dust aggregates over a 130 min long sequence, and find that their sizes are around a millimetre and their distances cluster between 2 and 40 m from the spacecraft. Their number densities are about a factor 10 higher than expected for the overall coma and highly fluctuating. Their velocities are small compared to the spacecraft orbital motion and directed away from the spacecraft, towards the comet. From this we conclude that they have interacted with the spacecraft and assess three possible scenarios. In the likeliest of the three scenarios, centimetre-sized aggregates collide with the spacecraft and we would observe the fragments. Ablation of a dust layer on the spacecraft's z panel (remote instrument viewing direction) when rotated towards the Sun is a reasonable alternative. We could also measure an acceleration for a subset of 18 aggregates, which is directed away from the Sun and can be explain by a rocket effect, which requires a minimum ice fraction of the order of 0.1 per cent.© 2017 The Authors., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017
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39. The highly active Anhur–Bes regions in the 67P/Churyumov–Gerasimenko comet: results from OSIRIS/ROSETTA observations

Author: Pedro Hasselmann, Philippe Lamy, Clement Feller, J. L. Bertaux, Xian Shi, M. F. A'Hearn, Olivier Groussin, M. De Cecco, Maurizio Pajola, M. L. Lara, J.-C. Lee, J.-B. Vincent, Holger Sierks, Stefano Mottola, Nilda Oklay, Marco Fulle, Wing-Huen Ip, Laurent Jorda, Cesare Barbieri, Imre Toth, Lorenza Giacomini, M. A. Barucci, Carsten Güttler, Jakob Deller, Sabrina Ferrari, V. Da Deppo, J. J. Lopez Moreno, Zhong-Yi Lin, Marc Hofmann, Sonia Fornasier, Detlef Koschny, Ivano Bertini, H. U. Keller, Nicolas Thomas, Michael Küppers, Jörg Knollenberg, Jessica Agarwal, Rafael Rodrigo, Giampiero Naletto, J. D. P. Deshapriya, Stefano Debei, Ekkehard Kührt, Géza Kovács, Gabriele Cremonese, Monica Lazzarin, Francesco Marzari, P. J. Gutiérrez, R. Kramm, Björn Davidsson, Matteo Massironi, Cecilia Tubiana, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Hans Rickman, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric Sciences [Taoyuan City], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Methods: observational, Techniques: photometric, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Outcrop, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Fault scarp, 01 natural sciences, Mantle (geology), 0103 physical sciences, Spectral slope, OSIRIS, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy, Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Plume, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 13. Climate action, Space and Planetary Science, Layering, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The Southern hemisphere of the 67P/Churyumov-Gerasimenko comet has become visible from Rosetta only since March 2015. It was illuminated during the perihelion passage and therefore it contains the regions that experienced the strongest heating and erosion rate, thus exposing the subsurface most pristine material. In this work we investigate, thanks to the OSIRIS images, the geomorphology, the spectrophotometry and some transient events of two Southern hemisphere regions: Anhur and part of Bes. Bes is dominated by outcropping consolidated terrain covered with fine particle deposits, while Anhur appears strongly eroded with elongated canyon-like structures, scarp retreats, different kinds of deposits, and degraded sequences of strata indicating a pervasive layering. We discovered a new 140 m long and 10 m high scarp formed in the Anhur/Bes boundary during/after the perihelion passage, close to the area where exposed CO$_2$ and H$_2$O ices were previously detected. Several jets have been observed originating from these regions, including the strong perihelion outburst, an active pit, and a faint optically thick dust plume. We identify several areas with a relatively bluer slope (i.e. a lower spectral slope value) than their surroundings, indicating a surface composition enriched with some water ice. These spectrally bluer areas are observed especially in talus and gravitational accumulation deposits where freshly exposed material had fallen from nearby scarps and cliffs. The investigated regions become spectrally redder beyond 2 au outbound when the dust mantle became thicker, masking the underlying ice-rich layers., 16 pages, 15 figures, published online on 24 May 2017 on Mon. Not. R. Astron. Soc. stx1275, https://doi.org/10.1093/mnras/stx1275
Published: 2017
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40. Seasonal erosion and restoration of the dust cover on comet 67P/Churyumov‐Gerasimenko as observed by OSIRIS onboard Rosetta

Author: Cesare Barbieri, Maria Antonieta Barucci, Jakob Deller, Gabriele Cremonese, Marco Fulle, Olivier Groussin, Jean-Loup Bertaux, J. Knollenberg, M. Küppers, Stefano Debei, Monica Lazzarin, L. M. Lara, Pedro J. Gutiérrez, Jean-Baptiste Vincent, C. Güttler, H. U. Keller, Maurizio Pajola, Géza Kovács, Ivano Bertini, Mohamed Ramy El-Maarry, Detlef Koschny, Hans Rickman, Nicolas Thomas, Holger Sierks, Sonia Fornasier, E. Kührt, A. Gicquel, J.-R. Kramm, Xian Shi, Dennis Bodewits, Nilda Oklay, X. Hu, V. Da Deppo, Björn Davidsson, Stefano Mottola, Cecilia Tubiana, Giampiero Naletto, P. Gutierrez-Marques, Rafael Rodrigo, Matteo Massironi, Stubbe F. Hviid, Jürgen Blum, Philippe Lamy, Wing-Huen Ip, Jessica Agarwal, Laurent Jorda, M. Hofmann, M. De Cecco, Bastian Gundlach, Steve Boudreault, J. J. López-Moreno, S. Höfner, Michael F. A'Hearn, Francesco Marzari, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), NASA Ames Research Center (ARC), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], Università degli Studi di Trento (UNITN), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Center for Space and Habitability (CSH), University of Bern, Max-Planck-Institut für Sonnensystemforschung (MPS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Universita degli Studi di Padova, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], European Space Agency, Centre National de la Recherche Scientifique (France), Agenzia Spaziale Italiana, Swedish National Space Board, Ministerio de Economía y Competitividad (España), International Max Planck Research Schools, German Centre for Air and Space Travel, and California Institute of Technology (CALTECH)-NASA
Subjects: Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet dust, Comet, Context (language use), Atmospheric sciences, 01 natural sciences, Latitude, Astrobiology, thermal modeling, individual: 67P/Churyumov [Comets], Rosetta, 0103 physical sciences, medicine, comets, Ejecta, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Physics, Polar night, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], general [Comets], Seasonality, erosion, medicine.disease, 13. Climate action, [SDU]Sciences of the Universe [physics], Erosion, sense organs
Abstract: Context. Dust deposits or dust cover are a prevalent morphology in the northern hemi-nucleus of comet 67P/Churyumov-Gerasimenko (67P). The evolution of the dust deposits was captured by the OSIRIS camera system onboard the Rosetta spacecraft having escorted the comet for over two years. The observations shed light on the fundamental role of cometary activity in shaping and transforming the surface morphology. Aims. We aim to present OSIRIS observations of surface changes over the dust deposits before and after perihelion. The distribution of changes and a timeline of their occurrence are provided. We perform a data analysis to quantify the surface changes and investigate their correlation to water activity from the dust deposits. We further discuss how the results of our investigation are related to other findings from the Rosetta mission. Methods. Surface changes were detected via systematic comparison of images, and quantified using shape-from-shading technique. Thermal models were applied to estimate the erosion of water ice in response to the increasing insolation over the areas where surface changes occurred. Modeling results were used for the interpretation of the observed surface changes. Results. Surface changes discussed here were concentrated at mid-latitudes, between about 20â-N and 40â-N, marking a global transition from the dust-covered to rugged terrains. The changes were distributed in open areas exposed to ample solar illumination and likely subject to enhanced surface erosion before perihelion. The occurrence of changes followed the southward migration of the sub-solar point across the latitudes of their distribution. The erosion at locations of most changes was at least about 0.5 m, but most likely did not exceed several meters. The erosive features before perihelion had given way to a fresh, smooth cover of dust deposits after perihelion, suggesting that the dust deposits had been globally restored by at least about 1 m with ejecta from the intensely illuminated southern hemi-nucleus around perihelion, when the north was inactive during polar night. Conclusions. The erosion and restoration of the northern dust deposits are morphological expressions of seasonality on 67P. Based on observations and thermal modeling results, it is inferred that the dust deposits contained a few percent of water ice in mass on average. Local inhomogeneity in water abundance at spatial scales below tens of meters is likely. We suspect that dust ejected from the deposits may not have escaped the comet in bulk. That is, at least half of the ejected mass was afloat in the inner-coma or/and redeposited over other areas of the nucleus.© 2017 ESO., X. Hu acknowledges the financial support from the International Max Planck Research School for Solar System Science in Gottingen.The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017
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41. Thermal modelling of water activity on comet 67P/Churyumov-Gerasimenko with global dust mantle and plural dust-to-ice ratio

Author: J.-R. Kramm, J.-B. Vincent, Michael Küppers, X. Hu, Gabriele Cremonese, J. J. López-Moreno, J. Agarwal, Marco Fulle, I. Hall, Maria Antonieta Barucci, M. F. A'Hearn, Björn Davidsson, Stefano Debei, Olivier Groussin, Ivano Bertini, J. Ripken, Maurizio Pajola, Ekkehard Kührt, Stubbe F. Hviid, Cecilia Tubiana, L. M. Lara, J. L. Bertaux, Giampiero Naletto, I. Büttner, Cesare Barbieri, Sonia Fornasier, Xian Shi, Nilda Oklay, R. Rodrigo, Juergen Oberst, Jakob Deller, Stefano Mottola, P. Gutierrez-Marques, C. Güttler, Detlef Koschny, Francesco Marzari, V. Da Deppo, Nicolas Thomas, P. J. Gutierrez, Jürgen Blum, Monica Lazzarin, Hans Rickman, Géza Kovács, H. U. Keller, Holger Sierks, Jörg Knollenberg, M. L. Richards, Wing-Huen Ip, Philippe Lamy, Laurent Jorda, Marc Hofmann, Steve Boudreault, M. De Cecco, Bastian Gundlach, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Technische Universität Berlin (TU), Institut für Geodäsie und Geoinformationstechnik, Moscow State University of Geodesy and Cartography (MIIGAiK), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), NASA Ames Research Center (ARC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], Center for Space and Habitability (CSH), University of Bern, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Technical University of Berlin / Technische Universität Berlin (TU), Università degli Studi di Padova = University of Padua (Unipd), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), and California Institute of Technology (CALTECH)-NASA
Subjects: Solid state: refractory, Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Insolation, 010504 meteorology & atmospheric sciences, Water activity, Comet, Volatile, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Mantle (geology), Solid state: volatile -methods: numerical, Astrobiology, 0103 physical sciences, Thermal, Comets, medicine, Comets: individual (67P/Churyumov-Gerasimenko), 010303 astronomy & astrophysics, Comets: general, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Refractory, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Planetengeodäsie, Astronomy and Astrophysics, Geophysics, 620 Engineering, medicine.anatomical_structure, Space and Planetary Science, Sublimation (phase transition), Numerical methods, Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nucleus
Abstract: International audience; We perform a thermo-physical analysis on water activity of comet 67P/Churyumov-Gerasimenko (67P). The sublimation of water is assumed to occur from beneath a global, desiccated dust mantle over the irregular-shaped nucleus. The concept of two thermal models, the recipe of model formulation and the strategy of application to comet 67P are described. For an accurate and efficient evaluation of energy input by insolation and self-heating over the nucleus, a Landscape data base is devised based on polyhedral shape models of the nucleus. We apply the thermal models to investigate the impact of certain parameters of nucleus properties on water production. It is found that the measured water production of 67P can be overall attributed to sublimation of water ice with a mass abundance of a few to 10 per cent beneath a uniform dust mantle of several millimetres to one centimetre in thickness. Insofar as 67P is concerned, we argue against the necessity to invoke assumptions on localized water activity, or on the distinction of active/dormant surface areas.
Published: 2017
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42. Dust mass distribution around comet 67P/Churyumov–Gerasimenko determined via parallax measurements using Rosetta's OSIRIS cameras

Author: J.-R. Kramm, P. J. Gutiérrez, M. F. A'Hearn, Olivier Groussin, J.-B. Vincent, Cesare Barbieri, E. Frattin, J. J. López-Moreno, Björn Poppe, Jakob Deller, M. De Cecco, Detlef Koschny, Nilda Oklay, Giampiero Naletto, Maurizio Pajola, Steve Boudreault, Zhong-Yi Lin, Clement Feller, V. Da Deppo, Marco Fulle, J. L. Bertaux, Géza Kovács, P. I. Lamy, Carsten Güttler, Wing-Huen Ip, Laurent Jorda, Francesco Marzari, E. Drolshagen, Stubbe F. Hviid, M. A. Barucci, Ivano Bertini, Marc Hofmann, Hans Rickman, Holger Sierks, Björn Davidsson, Jörg Knollenberg, Cecilia Tubiana, Monica Lazzarin, H. U. Keller, Jessica Agarwal, Bernhard Geiger, Michael Küppers, Sonia Fornasier, Xian Shi, T. Ott, Stefano Mottola, R. Rodrigo, A. Gicquel, Nicolas Thomas, Gabriele Cremonese, Ekkehard Kührt, L. M. Lara, Stefano Debei, University of Oldenburg, Carl Von Ossietzky Universität Oldenburg, Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Physikalisches Institut [Bern], Universität Bern [Bern], Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), NASA-California Institute of Technology (CALTECH), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, DEU, German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Ministerio de Economía y Competitividad (España), Swedish National Space Board, European Space Agency, Centre National de la Recherche Scientifique (France), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Asteroiden und Kometen, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Coma (optics), 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Rosetta, 0103 physical sciences, Spectral slope, image processing [Techniques], OSIRIS, 010303 astronomy & astrophysics, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Parallaxes, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Range (particle radiation), Mass distribution, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, general [Comets], Astronomy, Astronomy and Astrophysics, 620 Engineering, Space and Planetary Science, Particle, Parallax, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The OSIRIS (optical, spectroscopic and infrared remote imaging system) instrument on board the ESA Rosetta spacecraft collected data of 67P/Churyumov-Gerasimenko for over 2 yr. OSIRIS consists of two cameras, a Narrow Angle Camera and a Wide Angle Camera. For specific imaging sequences related to the observation of dust aggregates in 67P's coma, the two cameras were operating simultaneously. The two cameras are mounted 0.7 m apart from each other, as a result this baseline yields a parallax shift of the apparent particle trails on the analysed images directly proportional to their distance. Thanks to such shifts, the distance between observed dust aggregates and the spacecraft was determined. This method works for particles closer than 6000 m to the spacecraft and requires very few assumptions. We found over 250 particles in a suitable distance range with sizes of some centimetres, masses in the range of 10-10 kg and a mean velocity of about 2.4 m s relative to the nucleus. Furthermore, the spectral slope was analysed showing a decrease in the median spectral slope of the particles with time. The further a particle is from the spacecraft the fainter is its signal. For this reason, this was counterbalanced by a debiasing. Moreover, the dust mass-loss rate of the nucleus could be computed as well as the Af ρ of the comet around perihelion. The summed-up dust mass-loss rate for the mass bins 10-10 kg is almost 8300 kg s.© 2017 The Authors., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017
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43. Distance determination method of dust particles using Rosetta OSIRIS NAC and WAC data

Author: Ivano Bertini, Björn Poppe, Marco Fulle, Nilda Oklay, V. Da Deppo, M. De Cecco, Monica Lazzarin, J. J. Lopez Moreno, Wing-Huen Ip, Laurent Jorda, Clement Feller, J.-R. Kramm, Theresa Ott, P. Lamy, P. J. Gutierrez, R. Rodrigo, Esther Drolshagen, A. Gicquel, Detlef Koschny, Marc Hofmann, Xian Shi, Jessica Agarwal, M. F. A'Hearn, Olivier Groussin, Stubbe F. Hviid, Francesco Marzari, Cesare Barbieri, Gabriele Cremonese, J. L. Bertaux, Jakob Deller, Ekkehard Kührt, Hans Rickman, L. M. Lara, Carsten Güttler, Björn Davidsson, Cecilia Tubiana, H. U. Keller, Stefano Debei, Holger Sierks, M. A. Barucci, Giampiero Naletto, Jörg Knollenberg, Sonia Fornasier, Michael Küppers, Nicolas Thomas, Carl Von Ossietzky Universität Oldenburg, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Akademie der Wissenschaften zu Göttingen, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Agence Spatiale Européenne = European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: Asteroiden und Kometen, 67P/Churyumov-Gerasimenko, Offset (computer science), 010504 meteorology & atmospheric sciences, Infrared, Dust particles, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Rosetta, 0103 physical sciences, Comets, Dust, Parallax, Stereo observations, Astronomy and Astrophysics, Space and Planetary Science, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Spacecraft, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], business.industry, 520 Astronomy, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, biology.organism_classification, 620 Engineering, stereo observations, Computer Science::Computer Vision and Pattern Recognition, Physics::Space Physics, 67 P/Churyumov-Gerasimenko, dust, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, Astrophysics - Earth and Planetary Astrophysics
Abstract: International audience; The ESA Rosetta spacecraft has been tracking its target, the Jupiter-family comet 67 P/Churyumov-Gerasimenko, in close vicinity for over two years. It hosts the OSIRIS instruments: the Optical, Spectroscopic, and Infrared Remote Imaging System composed of two cameras, see e.g. Keller et al. (2007). In some imaging sequences dedicated to observe dust particles in the comet's coma, the two cameras took images at the same time.The aim of this work is to use these simultaneous double camera observations to calculate the dust particles’ distance to the spacecraft. As the two cameras are mounted on the spacecraft with an offset of 70 cm, the distance of particles observed by both cameras can be determined by a shift of the particles’ apparent trails on the images. This paper presents first results of the ongoing work, introducing the distance determination method for the OSIRIS instrument and the analysis of an example particle. We note that this method works for particles in the range of about 500 m – 6000 m from the spacecraft.
Published: 2017
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44. The pebbles/boulders size distributions on Sais: Rosetta’s final landing site on comet 67P/Churyumov–Gerasimenko

Author: M. F. A'Hearn, Cesare Barbieri, Matteo Massironi, Stubbe F. Hviid, Ekkehard Kührt, Xian Shi, Olivier Groussin, F. Scholten, Jörg Knollenberg, Jakob Deller, Stefano Mottola, Hans Rickman, L. M. Lara, Monica Lazzarin, Michael Küppers, J.-R. Kramm, Detlef Koschny, Maurizio Pajola, S. Höfner, Nicolas Thomas, Ivano Bertini, Björn Davidsson, Cecilia Tubiana, Maximilian Hamm, Alice Lucchetti, M. R. El Maarry, M. De Cecco, P. J. Gutierrez, Francesco Marzari, Holger Sierks, Gabriele Cremonese, Giampiero Naletto, Wing-Huen Ip, Laurent Jorda, Imre Toth, F. Preusker, Stefano Debei, Sonia Fornasier, Jessica Agarwal, Géza Kovács, Marc Hofmann, Marco Fulle, M. A. Barucci, R. Rodrigo, A. Gicquel, Harald Michalik, Philippe Lamy, H. U. Keller, J. J. Lopez Moreno, Carsten Güttler, J.-B. Vincent, E. Frattin, Luca Penasa, J. L. Bertaux, Nilda Oklay, V. Da Deppo, NASA Ames Research Center (ARC), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astronomico di Trieste (OAT), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Geoscienze [Padova], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Information Engineering [Padova] (DEI), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Industrial Engineering [Padova], University of Trento [Trento], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Universidad Politécnica de Madrid (UPM), Institut für Datentechnik und Kommunikationsnetze, Center for Space and Habitability (CSH), University of Bern, National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), Universität Bern [Bern] (UNIBE), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, Outcrop, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mineralogy, Terrain, Comets: individual (67P C-G), Methods: data analysis, Methods: statistical, comets: individual (67P C-G) - methods: data Analysis - methods: statistical, 01 natural sciences, Power law, Astronomy and Astrophysics, Space and Planetary Science, Methods statistical, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, 620 Engineering, Debris
Abstract: International audience; By using the imagery acquired by the Optical, Spectroscopic, and Infrared Remote Imaging System Wide-Angle Camera (OSIRIS WAC), we prepare a high-resolution morphological map of the Rosetta Sais final landing site, characterized by an outcropping consolidated terrain unit, a coarse boulder deposit and a fine particle deposit. Thanks to the 0.014 m resolution images, we derive the pebbles/boulders size-frequency distribution (SFD) of the area in the size range of 0.07–0.70 m. Sais’ SFD is best fitted with a two-segment differential power law: the first segment is in the range 0.07–0.26 m, with an index of −1.7 ± 0.1, while the second is in the range 0.26–0.50 m, with an index of −4.2 +0.4/−0.8. The ‘knee’ of the SFD, located at 0.26 m, is evident both in the coarse and fine deposits. When compared to the Agilkia Rosetta Lander Imaging System images, Sais surface is almost entirely free of the ubiquitous, cm-sized debris blanket observed by Philae. None the less, a similar SFD behaviour of Agilkia, with a steeper distribution above ∼0.3 m, and a flatter trend below that, is observed. The activity evolution of 67P along its orbit provides a coherent scenario of how these deposits were formed. Indeed, different lift pressure values occurring on the two locations and at different heliocentric distances explain the presence of the cm-sized debris blanket on Agilkia observed at 3.0 au inbound. Contrarily, Sais activity after 2.1 au outbound has almost completely eroded the fine deposits fallen during perihelion, resulting in an almost dust-free surface observed at 3.8 au.
Published: 2017
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45. Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images

Author: Cesare Barbieri, Nilda Oklay, Giampiero Naletto, Frank Scholten, Xian Shi, V. Da Deppo, Ekkehard Kührt, A. Gicquel, L. M. Lara, J. B. Vincent, Stefano Mottola, Carsten Güttler, P. Lamy, J.-R. Kramm, Géza Kovács, P. J. Gutierrez, Holger Sierks, B. J. R. Davidsson, Francesco Marzari, Jörg Knollenberg, M. De Cecco, M. A. Barucci, Rafael Rodrigo, Laurent Jorda, Stefano Debei, J. L. Bertaux, Marco Fulle, Sonia Fornasier, Marc Hofmann, M. F. A'Hearn, Olivier Groussin, W-H. Ip, I. Hall, Gabriele Cremonese, Clement Feller, Nafiseh Masoumzadeh, Pedro Hasselmann, J. J. Lopez Moreno, H. U. Keller, Ivano Bertini, Stubbe F. Hviid, Cecilia Tubiana, Monica Lazzarin, Ludmilla Kolokolova, Detlef Koschny, Nicolas Thomas, Michael Küppers, Frank Preusker, Hans Rickman, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science, National Central University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Swedish National Space Board, Ministerio de Economía y Competitividad (España), Agenzia Spaziale Italiana, Centre National de la Recherche Scientifique (France), German Centre for Air and Space Travel, European Space Agency, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, Solar System, Brightness, Opposition surge, 010504 meteorology & atmospheric sciences, Comets: individual: 67P/Churyumov-Gerasimenko, Planets and satellites: surfaces, Techniques: photometric, Astrophysics, Coherent backscattering, 01 natural sciences, individual: 67P/Churyumov [Comets], 0103 physical sciences, 010303 astronomy & astrophysics, Comets: individual: 67P/Churyumov, Gerasimenko, 0105 earth and related environmental sciences, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Space and Planetary Science, photometric [Techniques], Astronomy, Mars Exploration Program, Phase curve, Moons of Mars, Wavelength, 13. Climate action, Opposition effect, surfaces [Planets and satellites]
Abstract: Aims. We aim to explore the behavior of the opposition effect as an important tool in optical remote sensing on the nucleus of comet 67P/Churyumov-Gerasimenko (67P), using Rosetta-OSIRIS images acquired in different filters during the approach phase, July-August 2014 and the close flyby images on 14 of February 2015, which contain the spacecraft shadow. Methods. We based our investigation on the global and local brightness from the surface of 67P with respect to the phase angle, also known as phase curve. The local phase curve corresponds to a region that is located at the Imhotep-Ash boundary of 67P. Assuming that the region at the Imhotep-Ash boundary and the entire nucleus have similar albedo, we combined the global and local phase curves to study the opposition-surge morphology and constrain the structure and properties of 67P. The model parameters were furthermore compared with other bodies in the solar system and existing laboratory study. Results. We found that the morphological parameters of the opposition surge decrease monotonically with wavelength, whereas in the case of coherent backscattering this behavior should be the reverse. The results from comparative analysis place 67P in the same category as the two Mars satellites, Phobos and Deimos, which are notably different from all airless bodies in the solar system. The similarity between the surface phase function of 67P and a carbon soot sample at extremely small angles is identified, introducing regolith at the boundary of the Imhotep-Ash region of 67P as a very dark and fluffy layer.© ESO, 2017., The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged
Published: 2017
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46. Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past

Author: Wing-Huen Ip, Laurent Jorda, Carsten Güttler, Detlef Koschny, Michael Küppers, Nicolas Thomas, Monica Lazzarin, Björn Davidsson, Géza Kovács, Cecilia Tubiana, Marc Hofmann, J.-R. Kramm, Philippe Lamy, Maurizio Pajola, Ivano Bertini, M. A. Barucci, Dennis Bodewits, X. Hu, J. Knollenberg, Marco Fulle, J.-B. Vincent, Holger Sierks, M. De Cecco, Luisa Lara, H. U. Keller, Rafael Rodrigo, Stubbe F. Hviid, Frank Scholten, M. Ramy El-Maarry, Jean-Loup Bertaux, Giampiero Naletto, Francesco Marzari, Frank Preusker, Nilda Oklay, A.-T. Auger, Sebastien Besse, Pedro J. Gutiérrez, V. Da Deppo, Z.-Yi Lin, Cesare Barbieri, J. J. Lopez Moreno, Pedro Hasselmann, Sonia Fornasier, Antoine Pommerol, Hans Rickman, M. F. A'Hearn, Jakob Deller, Olivier Groussin, Clement Feller, Simone Marchi, Xian Shi, Stefano Mottola, Gabriele Cremonese, Ekkehard Kührt, J. D. P. Deshapriya, Stefano Debei, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Physikalisches Institut [Bern], Universität Bern [Bern], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), European Space Agency (ESA), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), Universität Bern [Bern] (UNIBE), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Weathering, 01 natural sciences, Astrobiology, 0103 physical sciences, Rosetta, OSIRIS, 010303 astronomy & astrophysics, NUCLEUS, 0105 earth and related environmental sciences, Multidisciplinary, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Medicine (all), IMHOTEP REGION, Surface, es, 13. Climate action, Amorphous ice, ROTATION, Environmental science, SHAPE
Abstract: International audience; The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by exposure to sunlight and other processes. While the localized changes suggest compositional or physical heterogeneity, their scale has not resulted in substantial alterations to the comet’s landscape. This suggests that most of the major landforms were created early in the comet’s current orbital configuration. They may even date from earlier if the comet had a larger volatile inventory, particularly of CO or CO2 ices, or contained amorphous ice, which could have triggered activity at greater distances from the Sun.
Published: 2017
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47. The opposition effect of 67P/Churyumov–Gerasimenko on post-perihelion Rosetta images

Author: Nilda Oklay, Cesare Barbieri, Stefano Mottola, V. Da Deppo, J.-B. Vincent, Jakob Deller, M. A. Barucci, Ekkehard Kührt, Francesco Marzari, M. De Cecco, G. Naletto, H. U. Keller, Bernhard Jost, R. Rodrigo, Jörg Knollenberg, J. L. Bertaux, Laurent Jorda, Marcello Fulchignoni, Michael Küppers, Michael F. A'Hearn, Carsten Güttler, J. D. P. Deshapriya, Stefano Debei, Marco Fulle, G. Cremonese, Marc Hofmann, Robert Gaskell, Sonia Fornasier, W-H. Ip, Holger Sierks, J. J. López-Moreno, M. L. Lara, Clement Feller, Géza Kovács, Philippe Lamy, P. J. Gutierrez, Pedro Hasselmann, Olivier Groussin, Monica Lazzarin, Björn Davidsson, Cecilia Tubiana, Stubbe F. Hviid, Ivano Bertini, R. Kramm, Detlef Koschny, Nicolas Thomas, Antoine Pommerol, Hans Rickman, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Planetary Science Institute [Tucson] (PSI), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Aix Marseille Université (AMU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Budapest University of Technology and Economics [Budapest] (BME), European Space Astronomy Centre (ESAC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), ITA, USA, GBR, FRA, DEU, and California Institute of Technology (CALTECH)-NASA
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Rosetta: 67P/Churyumov-Gerasimenko, Opposition (planets), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Photometry, 0103 physical sciences, Rosetta, OSIRIS, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy, Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, Opposition Effect, Space and Planetary Science, Rosetta:67P/Churyumov-Gerasimenko, Osiris
Abstract: International audience; High-resolution OSIRIS/Rosetta images of 67P/Churyumov-Gerasimenko acquired on the night run of April 9th to 10th 2016 shows, at large scale, an Opposition Effect (OE) spot swooping across Imhotep as the phase angle ranges from 0° to 17°. In this work, we fitted the phase curve of the whole surface imaged as well as three particular features using both linear-exponential and Hapke (2012) model. Those features encompass different types of spectral behaviour: a circular mesa, one venous structure and an assemble of bright spots, going from red to blue colours. Both Hapke and linear-exponential parameters indicate a stepwise sharpening of the OE from bright spots to circular mesa. Yet, a very broad non-linear phase curve is verified and no sign of sharp OE associated to coherent-backscattering mechanism observed. We estimate that 67P surface is dominated by opaque, desiccated and larger-than-wavelength irregular grains. Veins and bright spots display photometric properties consistent to surfaces becoming slightly brighter as it is enriched by high albedo ice grains. We also report the estimation of normal albedo for all cometary regions observed throughout the image sequence. Comparison to pre-perihelion results (Fornasier et al., 2015) indicates that far better insolation of northern brighter regions, i.e. Hapi, Hathor and Seth, is sufficient to explain mismatches on the photometric parameters. However, metre-scale photometric analysis of Imhotep-Ash boundary area (Feller et al., 2016) advocates for mild darkening (< 7%) of the surface at local scale.
Published: 2017
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48. Rosetta’s comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature

Author: M. Küppers, Maurizio Pajola, M. L. Lara, Giampiero Naletto, Jean-Loup Bertaux, J. D. P. Deshapriya, J. J. Lopez Moreno, Imre Toth, Ivano Bertini, Nilda Oklay, M. A. Barucci, Frank Scholten, Gabriele Cremonese, M. De Cecco, V. Da Deppo, Marco Fulle, Sonia Fornasier, Wing-Huen Ip, Olivier Groussin, Laurent Jorda, E. Kührt, Holger Sierks, Géza Kovács, Cesare Barbieri, Sebastien Besse, Jakob Deller, J. Knollenberg, Antoine Pommerol, Björn Davidsson, Stefano Debei, Philippe Lamy, R. Kramm, Cecilia Tubiana, C. Güttler, H. U. Keller, Rafael Rodrigo, Monica Lazzarin, Xian Shi, Jean-Baptiste Vincent, Stefano Mottola, Jessica Agarwal, Pedro J. Gutiérrez, Clement Feller, M. Hofmann, Matteo Massironi, Detlef Koschny, Nicolas Thomas, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Hans Rickman, Francesco Marzari, Frank Preusker, Michael F. A'Hearn, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern], INAF - Osservatorio Astronomico di Trieste (OAT), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Information Engineering [Padova] (DEI), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), NASA Ames Research Center (ARC), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, osiris, H2O ICE, 01 natural sciences, EXPOSED WATER ICE, Mantle (geology), Nucleus, Astrobiology, rosetta, comet, 0103 physical sciences, morphology, medicine, surface, virtis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Multidisciplinary, Medicine (all), medicine.anatomical_structure, data, 13. Climate action, [SDU]Sciences of the Universe [physics], Cyclic process, Sublimation (phase transition), Water ice, Surface dust, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: Rosetta observes sublimating surface ices Comets are “dirty snowballs” made of ice and dust, but they are dark because the ice sublimates away, leaving some of the dust behind on the surface. The Rosetta spacecraft has provided a close-up view of the comet 67P/Churyumov-Gerasimenko as it passes through its closest point to the Sun (see the Perspective by Dello Russo). Filacchione et al. detected the spectral signature of solid CO 2 (dry ice) in small patches on the surface of the nucleus as they emerged from local winter. By modeling how the CO 2 sublimates, they constrain the composition of comets and how ices generate the gaseous coma and tail. Fornasier et al. studied images of the comet and discovered bright patches on the surface where ice was exposed, which disappeared as the ice sublimated. They also saw frost emerging from receding shadows. The surface of the comet was noticeably less red just after local dawn, indicating that icy material is removed by sunlight during the local day. Science , this issue p. 1563 , p. 1566 ; see also p. 1536
Published: 2016
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49. Spectrophotometry of the Khonsu region on the comet 67P/Churyumov-Gerasimenko using OSIRIS instrument images

Author: Steve Boudreault, Ivano Bertini, Rafael Rodrigo, Philippe Lamy, Cesare Barbieri, Detlef Koschny, Olivier Groussin, Nicolas Thomas, Jakob Deller, Stefano Debei, Antoine Pommerol, Francesco Marzari, M. A. Barucci, J. D. P. Deshapriya, Pedro Hasselmann, Sonia Fornasier, Stubbe F. Hviid, Björn Davidsson, Jean-Loup Bertaux, J. J. Lopez Moreno, Clement Feller, Holger Sierks, Cecilia Tubiana, Jessica Agarwal, Michael F. A'Hearn, Marco Fulle, Stefano Mottola, Nilda Oklay, R. Kramm, Pedro J. Gutiérrez, Gabriele Cremonese, Ekkehard Kührt, Maurizio Pajola, Monica Lazzarin, L. M. Lara, A. Gicquel, Jean-Baptiste Vincent, Michael Küppers, V. Da Deppo, M. De Cecco, Wing-Huen Ip, Laurent Jorda, Mohamed Ramy El-Maarry, Hans Rickman, Marc Hofmann, J. Knollenberg, Giampiero Naletto, H. U. Keller, Carsten Güttler, D. Perna, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), NASA Ames Research Center (ARC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Industrial Engineering [Padova], Università degli Studi di Trento (UNITN), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Centre National de la Recherche Scientifique (France), German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Swedish National Space Board, European Space Agency, Ministerio de Economía y Competitividad (España), Max-Planck-Institut für Sonnensystemforschung (MPS), Universität Bern [Bern], Universita degli Studi di Padova, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, 530 Physics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, Astronomi, astrofysik och kosmologi, individual: 67P/Churyumov-Gerasimenko [Comets], Spectrophotometry, 0103 physical sciences, medicine, techniques: photometric comets: individual: 67P/Churyumov-Gerasimenko, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, biology, medicine.diagnostic_test, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, photometric [Techniques], Astronomy, Astronomy and Astrophysics, biology.organism_classification, 620 Engineering, techniques: photometric – comets: individual: 67P/Churyumov-Gerasimenko, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Techniques: photometric, Osiris
Abstract: Our work focuses on the spectrophotometric analysis of selected terrain and bright patches in the Khonsu region on the comet 67P/Churyumov-Gerasimenko. Despite the variety of geological features, their spectrophotometric properties appear to indicate a similar composition. It is noticeable that the smooth areas in Khonsu possess similar spectrophotometric behaviour to some other regions of the comet. We observed bright patches on Khonsu with an estimation of > 40 per cent of normal albedo and suggest that they are associated with HO ice. One of the studied bright patches has been observed to exist on the surface for more than 5 months without a major decay of its size, implying the existence of potential sub-surface icy layers. Its location may be correlated with a cometary outburst during the perihelion passage of the comet in 2015 August, and we interpret it to have triggered the surface modifications necessary to unearth the stratified icy layers beneath the surface. A boulder analysis on Khonsu leads to a power-law index of -3.1 +0.2/-0.3 suggesting a boulder formation, shaped by varying geological processes for different morphological units.© 2016 The Authors., The support of the national funding agencies of Germany (DLR), France(CNES), Italy(ASI), Spain(MEC), Sweden(SNSB) and the ESA Technical Directorate is gratefully acknowledged.
Published: 2016
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50. The southern hemisphere of 67P/Churyumov-Gerasimenko: Analysis of the preperihelion size-frequency distribution of boulders ≥7 m

Author: Michael F. A'Hearn, Mohamed Ramy El-Maarry, Holger Sierks, Maurizio Pajola, Nilda Oklay, Luisa Lara, Hans Rickman, Ivano Bertini, Cesare Barbieri, Jakob Deller, Zhong-Yi Lin, Frank Scholten, Giampiero Naletto, Frank Preusker, Jessica Agarwal, Detlef Koschny, N. Thomas, Ekkehard Kührt, S. Höfner, Stefano Mottola, Michael Küppers, Maria Antonietta Barucci, Carsten Güttler, Matteo Massironi, Francesco Marzari, Jörg Knollenberg, Jose J. Lopez Moreno, Stubbe F. Hviid, H. U. Keller, Björn Davidsson, A. Gicquel, Rafael Rodrigo, Cecilia Tubiana, Gabriele Cremonese, Jean-Loup Bertaux, J. Rainer Kramm, Marco Fulle, Fiorangela La Forgia, Stefano Debei, Imre Toth, Monica Lazzarin, Sonia Fornasier, Jean-Baptiste Vincent, Mariolino De Cecco, Philippe Lamy, Jui Chi Lee, Harald Michalik, Steve Boudreault, Vania Da Deppo, Pedro J. Gutiérrez, Alice Lucchetti, Olivier Groussin, Wing-Huen Ip, Laurent Jorda, Marc Hofmann, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Physikalisches Institut [Bern], Universität Bern [Bern], Department of Information Engineering [Padova] (DEI), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Institute of Computer and Network Engineering [Braunschweig] (IDA), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Universität Bern [Bern] (UNIBE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), and California Institute of Technology (CALTECH)-NASA
Subjects: Physics, Comets: individual: 67P/Churyumov-Gerasimenko, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet, Northern Hemisphere, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Narrow angle, High resolution, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Comets: general, comets: general / comets: individual: 67P/Churyumov-Gerasimenko / methods: data analysis, Methods: data analysis, Space and Planetary Science, 13. Climate action, 0103 physical sciences, Size frequency, Comets, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences
Abstract: Aims: We calculate the size-frequency distribution of the boulders on the southern hemisphere of comet 67P Churyumov-Gerasimenko (67P), which was in shadow before the end of April 2015. We compare the new results with those derived from the northern hemisphere and equatorial regions of 67P, highlighting the possible physical processes that lead to these boulder size distributions. Methods: We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 2 May 2015 at a distance of 125 km from the nucleus. The scale of this dataset is 2.3 m/px; the high resolution of the images, coupled with the favorable observation phase angle of 62°, provided the possibility to unambiguously identify boulders ≥7 m on the surface of 67P and to manually extract them with the software ArcGIS. We derived the size-frequency distribution of the illuminated southern hemisphere. Results: We found a power-law index of -3.6 ± 0.2 for the boulders on the southern hemisphere with a diameter range of 7-35 m. The power-law index is equal to the one previously found on northern and equatorial regions of 67P, suggesting that similar boulder formation processes occur in both hemispheres. The power-law index is related to gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. In addition, the presence of a larger number of boulders per km2 in the southern hemisphere, which is a factor of 3 higher with respect to the northern hemisphere, suggests that the southernmost terrains of 67P are affected by a stronger thermal fracturing and sublimating activity, hence possibly causing larger regressive erosion and gravitational events.
Published: 2016
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