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132 results on '"M. F. A'Hearn"'

1. ROSETTA: How to archive more than 10 years of mission

Author: F. Vallejo, P. Martin, David Heather, Sebastien Besse, M. F. A'Hearn, D. Fraga, E. Grotheer, Matthew Taylor, Ludmilla Kolokolova, Maud Barthelemy, R. Andres, Laurence O'Rourke, and T. Barnes
Subjects: Scientific instrument, Engineering, 010504 meteorology & atmospheric sciences, business.industry, Astronomy and Astrophysics, 01 natural sciences, Planetary Data System, Astrobiology, Planetary science, Aeronautics, Space and Planetary Science, 0103 physical sciences, Comet (programming), Data content, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: The Rosetta spacecraft was launched in 2004 and, after several planetary and two asteroid fly-bys, arrived at comet 67P/Churyumov-Gerasimenko in August 2014. After escorting the comet for two years and executing its scientific observations, the mission ended on 30 September 2016 through a touch down on the comet surface. This paper describes how the Planetary Science Archive (PSA) and the Planetary Data System – Small Bodies Node (PDS-SBN) worked with the Rosetta instrument teams to prepare the science data collected over the course of the Rosetta mission for inclusion in the science archive. As Rosetta is an international mission in collaboration between ESA and NASA, all science data from the mission are fully archived within both the PSA and the PDS. The Rosetta archiving process, supporting tools, archiving systems, and their evolution throughout the mission are described, along with a discussion of a number of the challenges faced during the Rosetta implementation. The paper then presents the current status of the archive for each of the science instruments, before looking to the improvements planned both for the archive itself and for the Rosetta data content. The lessons learned from the first 13 years of archiving on Rosetta are finally discussed with an aim to help future missions plan and implement their science archives.
Published: 2018

2. Abundances and spatial distributions of H2O and CO2 at comet 9P/Tempel 1 during a natural outburst

Author: M. F. A'Hearn, Lori M. Feaga, and M.J. Moretto
Subjects: Physics, 010504 meteorology & atmospheric sciences, Space and Planetary Science, Abundance (ecology), 0103 physical sciences, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Abstract: On approach to comet 9P/Tempel 1, Deep Impact observed about one dozen natural outbursts. One of the largest occurred on 2 July 2005 and was also captured by Deep Impact's infrared spectrometer, HRI-IR. HRI-IR operates between 1.05 and 4.86 µm, allowing it to detect H 2 O (2.67 µm) and CO 2 (4.27 µm) emission bands simultaneously. In the hours leading up to the outburst, both H 2 O and CO 2 behaved quiescently, consistent with previously published studies. During the outburst, CO 2 abundance increased by 40% while H 2 O abundance stayed constant. No additional species were detectable during the outburst. The distribution of CO 2 during the outburst is correlated with that of the dust, observed at the same time in the visible. The abundance of CO 2 returned to quiescent levels within 3.6 h of outburst onset. A slight enhancement in H 2 O was observed well after the outburst, though this does not appear to be correlated with the outburst. From this analysis, it is likely that CO 2 was a driver of the 2 July 2005 outburst and that H 2 O was not.
Published: 2017

3. 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

4. Evidence of sub-surface energy storage in comet 67P from the outburst of 2016 July 03

Author: M. A. Barucci, Eberhard Grün, Giampiero Naletto, Ivano Bertini, M. De Cecco, Pedro Hasselmann, S. Mottola, Wing-Huen Ip, Laurent Jorda, Bernhard Geiger, Xian Shi, Maurizio Pajola, Jouni Rynö, Gabriele Cremonese, Oliver Stenzel, J. J. Lopez Moreno, J. L. Bertaux, J. Kissel, S. Höfner, M. F. A'Hearn, Olivier Groussin, Martin Hilchenbach, B. Zaprudin, Steve Boudreault, V. Da Deppo, Alessandra Rotundi, Ludmilla Kolokolova, Dennis Bodewits, Philippe Lamy, Jessica Agarwal, Marc Hofmann, Paul D. Feldman, Horst Uwe Keller, Stefano Debei, Sihane Merouane, J. Wm. Parker, Monica Lazzarin, Stubbe F. Hviid, Michael Küppers, Stavro Ivanovski, Cesare Barbieri, Jean-Baptiste Vincent, Francesco Marzari, Detlef Koschny, Yves Langevin, Sonia Fornasier, N. Oklay, L. M. Lara, Jakob Deller, Zhong-Yi Lin, A. Koch, Andrew J. Steffl, R. Rodrigo, Björn Davidsson, J.-R. Kramm, Carsten Güttler, E. Kührt, Cecilia Tubiana, Klaus Hornung, P. J. Gutierrez, Stephen C. Lowry, Jörg Knollenberg, Holger Sierks, Henning Fischer, Marco Fulle, V. Della Corte, A. Gicquel, Harold A. Weaver, Nicolas Thomas, Lori M. Feaga, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), 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), Max-Planck-Institut für Kernphysik (MPIK), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Dipartimento di Fisica e Astronomia 'Galileo Galilei', 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 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], 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'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität der Bundeswehr München [Neubiberg], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), 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], von Hoerner und Sulger GmbH, European Space Research and Technology Centre (ESTEC), Research and Scientific Support Department, ESTEC (RSSD), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), Finnish Meteorological Institute (FMI), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Tuorla Observatory, University of Turku, Lowry, S.C., ITA, FRA, DEU, ESP, Centre National de la Recherche Scientifique (France), German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Swedish National Space Board, Ministerio de Economía y Competitividad (España), European Space Agency, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli studi di Napoli 'Parthenope' [Napoli], European Space Agency (ESA), Universita degli Studi di Padova, Universität Bern [Bern], 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), Consiglio Nazionale delle Ricerche [Roma] (CNR), California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Asteroiden und Kometen, Solid state: refractory, Acceleration of particles, 010504 meteorology & atmospheric sciences, 01 natural sciences, law.invention, Astrobiology, Scattering, individual: 67P/Churyumov-Gerasimenko [Comets], law, Rosetta, 0103 physical sciences, Surface change, Astrophysics::Solar and Stellar Astrophysics, Sunrise, OSIRIS, Solid state: volatile, Crystallization, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Comets: individual: 67P/Churyumov-Gerasimenko, [PHYS]Physics [physics], Physics, ta115, 520 Astronomy, volatile [Solid state], general [Comets], Astronomy and Astrophysics, Solar illumination, 620 Engineering, Surface energy, Amorphous solid, Comets: general, On board, 13. Climate action, Space and Planetary Science, acceleration of particles, scattering, solid state: refractory, solid state: volatile, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, Physics::Space Physics, Sublimation (phase transition), QB651, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], refractory [Solid state]
Abstract: On 2016 July 03, several instruments onboard ESA's Rosetta spacecraft detected signs of an outburst event on comet 67P, at a heliocentric distance of 3.32 au from the Sun, outbound from perihelion. We here report on the inferred properties of the ejected dust and the surface change at the site of the outburst. The activity coincided with the local sunrise and continued over a time interval of 14-68 min. It left a 10-m-sized icy patch on the surface. The ejected material comprised refractory grains of several hundred microns in size, and sub-micron-sized water ice grains. The high dust mass production rate is incompatible with the free sublimation of crystalline water ice under solar illumination as the only acceleration process. Additional energy stored near the surface must have increased the gas density. We suggest a pressurized sub-surface gas reservoir, or the crystallization of amorphous water ice as possible causes.© 2015 The Authors., The support of the national funding agencies of Germany (DLR, grant 50 QP 1302), France (CNES), Austria, Finland and the ESA Technical Directorate is gratefully acknowledged.
Published: 2017

5. 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

6. Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015

Author: P. K. Seidelmann, Randolph L. Kirk, Brent A. Archinal, Daniel Hestroffer, Iwan P. Williams, Guy J. Consolmagno, Sergei A. Klioner, Peter C. Thomas, Karen J. Meech, David J. Tholen, J. L. Hilton, Thomas C. Duxbury, A. Conrad, Dennis D. McCarthy, J. Ping, M. F. A'Hearn, Juergen Oberst, C. H. Acton, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-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), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Computer science, Satellites, Dwarf planet, Planets, Planetographic, 01 natural sciences, Rotation periods, Jupiter, Neptune, Planet, Coordinate frames, 0103 physical sciences, Planetocentric, Comets, 010303 astronomy & astrophysics, Mathematical Physics, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Dwarf planets, Latitude, Applied Mathematics, Coordinate systems, Minor planets, Astronomy and Astrophysics, Exoplanet, Asteroids, Pluto, Computational Mathematics, Longitude, 13. Climate action, Space and Planetary Science, Asteroid, Modeling and Simulation, Rotation axes, Sizes, Great conjunction, Shapes, Cardinal directions, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Cartography, Cartographic coordinates
Abstract: International audience; This report continues the practice where the IAU Working Group on Cartographic Coordinates and Rotational Elements revises recommendations regarding those topics for the planets, satellites, minor planets, and comets approximately every 3 years. The Working Group has now become a "functional working group" of the IAU, and its membership is open to anyone interested in participating. We describe the procedure for submitting questions about the recommendations given here or the application of these recommendations for creating a new or updated coordinate system for a given body. Regarding body orientation, the following bodies have been updated: Mercury, based on MESSENGER results; Mars, along with a refined longitude definition; Phobos; Deimos; (1) Ceres; (52) Europa; (243) Ida; (2867) Šteins; Neptune; (134340) Pluto and its satellite Charon; comets 9P/Tempel 1, 19P/Borrelly, 67P/Churyumov-Gerasimenko, and 103P/Hartley 2, noting that such information is valid only between specific epochs. The special challenges related to mapping 67P/Churyumov-Gerasimenko are also discussed. Approximate expressions for the Earth have been removed in order to avoid confusion, and the low precision series expression for the Moon's orientation has been removed. The previously online only recommended orientation model for (4) Vesta is repeated with an explanation of how it was updated. Regarding body shape, text has been included to explain the expected uses of such information, and the relevance of the cited uncertainty information. The size of the Sun has been updated, and notation added that the size and the ellipsoidal axes for the Earth and Jupiter have been recommended by an IAU Resolution. The distinction of a reference radius for a body (here, the Moon and Titan) is made between cartographic uses, and for orthoprojection and geophysical uses. The recommended radius for Mercury has been updated based on MESSENGER results. The recommended radius for Titan is returned to its previous value. Size information has been updated for 13 other Saturnian satellites and added for Aegaeon. The sizes of Pluto and Charon have been updated. Size information has been updated for (1) Ceres and given for (16) Psyche and (52) Europa. The size of (25143) Itokawa has been corrected. In addition, the discussion of terminology for the poles (hemispheres) of small bodies has been modified and a discussion on cardinal directions added. Although they continue to be used for planets and their satellites, it is assumed that the planetographic and planetocentric coordinate system definitions do not apply to small bodies. However, planetocentric and planetodetic latitudes and longitudes may be used on such bodies, following the right-hand rule. We repeat our previous recommendations that planning and efforts be made to make controlled cartographic products; newly recommend that common formulations should be used for orientation and size; continue to recommend that a community consensus be developed for the orientation models of Jupiter and Saturn; newly recommend that historical summaries of the coordinate systems for given bodies should be developed, and point out that for planets and satellites planetographic systems have generally been historically preferred over planetocentric systems, and that in cases when planetographic coordinates have been widely used in the past, there is no obvious advantage to switching to the use of planetocentric coordinates. The Working Group also requests community input on the question submitting process, posting of updates to the Working Group website, and on whether recommendations should be made regarding exoplanet coordinate systems.
Published: 2018

7. 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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8. 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

9. 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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10. 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

11. 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

12. 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

13. Constraints on cometary surface evolution derived from a statistical analysis of 67P's topography

Author: E. Kuehrt, Luca Penasa, Giampiero Naletto, Marco Fulle, A. Gicquel, Cesare Barbieri, Francesco Marzari, J. L. Bertaux, Stefano Mottola, Ivano Bertini, F. Preusker, Carsten Güttler, Jakob Deller, Gabriele Cremonese, Zhong-Yi Lin, F. Scholten, Géza Kovács, Hans Rickman, Steve Boudreault, Monica Lazzarin, Jörg Knollenberg, L. M. Lara, V. Da Deppo, M. A. Barucci, Michael Küppers, Holger Sierks, Stubbe F. Hviid, Detlef Koschny, J. J. Lopez Moreno, M. De Cecco, P. Gutiérrez-Marquez, Nicolas Thomas, Björn Davidsson, Cecilia Tubiana, Xian Shi, Imre Toth, N. Oklay, Philippe Lamy, Stefano Debei, Maurizio Pajola, X. Hu, Wing-Huen Ip, J. B. Vincent, J.-R. Kramm, Laurent Jorda, Sonia Fornasier, D. de Niem, Marc Hofmann, P. J. Gutierrez, Clement Feller, R. Rodrigo, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, 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, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), 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, 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, 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', 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), European Space Agency (ESA), 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), Department of Industrial Engineering [Padova], University of Trento [Trento], 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), Department of Information Engineering [Padova] (DEI), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Dipartimento di Geoscienze [Padova], Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), NASA-California Institute of Technology (CALTECH), 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), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), 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), and Universität Bern [Bern] (UNIBE)
Subjects: Surface (mathematics), 010504 meteorology & atmospheric sciences, Distribution (number theory), Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, 01 natural sciences, comet, surface evolution, topography, statistical analysis, Rosetta, 0103 physical sciences, Statistical analysis, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, [PHYS]Physics [physics], 67P, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Comets: individual: 67P, Astronomy and Astrophysics, Geophysics, Comets: general, 620 Engineering, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present a statistical analysis of the distribution of large-scale topographic features on comet 67P/Churyumov-Gerasimenko.We observe that the cumulative cliff height distribution across the surface follows a power law with a slope equal to -1.69 ± 0.02. When this distribution is studied independently for each region, we find a good correlation between the slope of the power law and the orbital erosion rate of the surface. For instance, the Northern hemisphere topography is dominated by structures on the 100 m scale, while the Southern hemisphere topography, illuminated at perihelion, is dominated by 10 m scale terrain features. Our study suggests that the current size of a cliff is controlled not only by material cohesion but also by the dominant erosional process in each region. This observation can be generalized to other comets, where we argue that primitive nuclei are characterized by the presence of large cliffs with a cumulative height-power index equal to or above -1.5, while older, eroded cometary surfaces have a power index equal to or below -2.3. In effect, our model shows that a measure of the topography provides a quantitative assessment of a comet's erosional history, that is, its evolutionary age. © 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.
Published: 2017

14. Post-perihelion photometry of dust grains in the coma of 67P Churyumov-Gerasimenko

Author: Carsten Güttler, Xian Shi, Ekkehard Kührt, L. M. Lara, Alice Lucchetti, Cesare Barbieri, J. B. Vincent, Stefano Mottola, P. Lamy, Hans Rickman, P. J. Gutierrez, Theresa Ott, Jakob Deller, Matteo Massironi, Jörg Knollenberg, Luca Penasa, Stubbe F. Hviid, Holger Sierks, Michael Küppers, F. La Forgia, J.-R. Kramm, J. L. Bertaux, Nilda Oklay, Ivano Bertini, Gabriele Cremonese, Wing-Huen Ip, Laurent Jorda, M. A. Barucci, Monica Lazzarin, J. J. Lopez Moreno, M. F. A'Hearn, Stefano Debei, Olivier Groussin, E. Frattin, V. Da Deppo, Emanuele Simioni, B. J. R. Davidsson, Horst Uwe Keller, Marc Hofmann, R. Rodrigo, Maurizio Pajola, A. Gicquel, Cecilia Tubiana, Sonia Fornasier, M. De Cecco, Giampiero Naletto, Francesco Marzari, Francesca Ferri, Jessica Agarwal, Marco Fulle, Detlef Koschny, Esther Drolshagen, Sabrina Ferrari, Nicolas Thomas, ITA, USA, GBR, FRA, DEU, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Università degli Studi di Padova = University of Padua (Unipd), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Oldenburg, Carl Von Ossietzky Universität Oldenburg = Carl von Ossietzky University of Oldenburg (OFFIS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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], 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], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), 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), European Space Astronomy Centre (ESAC), Dipartimento di Geoscienze [Padova], Department of Information Engineering [Padova] (DEI), NASA Ames Research Center (ARC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Carl Von Ossietzky Universität Oldenburg, Max-Planck-Institut für Sonnensystemforschung (MPS), 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, 010504 meteorology & atmospheric sciences, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, Spectral line, Photometry (optics), Photometry, Methods: data analysis, 0103 physical sciences, Spectral slope, Rosetta, Comets, OSIRIS, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Zodiacal dust, Astronomy and Astrophysics, 620 Engineering, Comets: general, Wavelength, Techniques: photometric, Space and Planetary Science, Water ice, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Automated method
Abstract: International audience; We present a photometric analysis of individual dust grains in the coma of comet 67P/Churyumov–Gerasimenko using OSIRIS images taken from 2015 July to 2016 January. We analysed a sample of 555 taken during 18 d at heliocentric distances ranging between 1.25 and 2.04 au and at nucleocentric distances between 80 and 437 km. An automated method to detect the tracks was specifically developed. The images were taken by OSIRIS NAC in four different filters: Near-IR (882 nm), Orange (649 nm), FarOrange (649 nm) and Blue (480 nm). It was not always possible to recognize all the grains in the four filters, hence we measured the spectral slope in two wavelengths ranges: in the interval [480–649] nm, for 1179 grains, and in the interval [649–882] nm, for 746 grains. We studied the evolution of the two populations’ average spectral slopes. The data result scattered around the average value in the range [480–649] nm, while in the [649–882] nm we observe a slight decreasing moving away from the Sun as well as a slight increasing with the nucleocentric distance. A spectrophotometric analysis was performed on a subsample of 339 grains. Three major groups were defined, based on the spectral slope between [535–882] nm: (i) the steep spectra that may be related with organic material, (ii) the spectra with an intermediate slope, likely a mixture of silicates and organics and (iii) flat spectra that may be associated with a high abundance of water ice.
Published: 2017

15. Geomorphological and spectrophotometric analysis of Seth's circular niches on comet 67P/Churyumov–Gerasimenko using OSIRIS images

Author: Monica Lazzarin, M. F. A'Hearn, Björn Davidsson, Cecilia Tubiana, Marco Fulle, Olivier Groussin, Frank Scholten, J.-B. Vincent, Sabrina Ferrari, Ekkehard Kührt, Xian Shi, Horst Uwe Keller, Stefano Mottola, L. M. Lara, Ivano Bertini, Michael Küppers, P. J. Gutierrez, Steve Boudreault, R. Rodrigo, Alice Lucchetti, Carsten Güttler, L. Z. Lin, F. La Forgia, Cesare Barbieri, Nilda Oklay, Jakob Deller, Holger Sierks, Sonia Fornasier, Detlef Koschny, Nicolas Thomas, V. Da Deppo, Maurizio Pajola, Clement Feller, Wing-Huen Ip, Laurent Jorda, M. Hoffman, Giampiero Naletto, Pedro Hasselmann, Jörg Knollenberg, J.-R. Kramm, Luca Penasa, G. Cremonese, Stefano Debei, M. De Cecco, J. L. Bertaux, J. J. Lopez Moreno, Philippe Lamy, M. A. Barucci, Matteo Massironi, Stubbe F. Hviid, Jessica Agarwal, Francesco Marzari, Hans Rickman, Frank Preusker, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), NASA Ames Research Center (ARC), 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), 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), Dipartimento di Geoscienze [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', 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], 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), 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), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), European Space Astronomy Centre (ESAC), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), 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), Consiglio Nazionale delle Ricerche [Roma] (CNR), Max-Planck-Institut für Sonnensystemforschung (MPS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), European Space Agency (ESA), Universität Bern [Bern], and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, comets: general-comets, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Terrain, 67P/Churyumov–Gerasimenko, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko-methods:data analysis, Methods: data analysis, 0103 physical sciences, Size frequency, Cliff, 010303 astronomy & astrophysics, Geomorphology, 0105 earth and related environmental sciences, Remote sensing, Comets: individual: 67P/Churyumov, Gerasimenko, Physics, Ecological niche, Comets: general, geography, geography.geographical_feature_category, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Astronomy and Astrophysics, Landslide, biology.organism_classification, 620 Engineering, 13. Climate action, Space and Planetary Science, Water ice, Osiris
Abstract: International audience; We provide a detailed geomorphological and spectrophotometric analysis of the circular niches located on the Seth region of 67P using OSIRIS images. The features can be related to landslide events that occurred on 67P and shaped its surface, as the recent Aswan cliff collapse detected in the same region. We therefore provide an analysis of the area pre- and post-perihelion suggesting that no specific changes have been observed. To assess this, after performing a geomorphological map of the area that allows us to identify different terrain units, we computed the boulders cumulative size frequency distribution (SFD) of the niches, before and after the perihelion passage. The niches SFDs are characterized by a similar trend with two different power-law indices within the same deposit: lower power-law value (between −2.3 and −2.7) for boulders smaller than 5 m and steeper power-law value (between −4.7 and −5.0) for boulders larger than 5 m. These trends suggest that smaller boulders have evolved and progressively have been depleted (lower power-law index), while bigger boulders are more representative of the event that generated the deposit and are less degraded. Then, we perform the spectrophotometric analysis of this region comparing pre- and post-perihelion results. We found colour changes within the area, in particular brighter patches related to the presence of exposed water ice mixed to the refractory materials have been detected in the post-perihelion images.
Published: 2017

16. Investigating the physical properties of outbursts on comet 67P/Churyumov-Gerasimenko

Author: I. L. Lai, W-H. Ip, Xian Shi, Holger Sierks, Stefano Mottola, Ivano Bertini, Laurent Jorda, Dennis Bodewits, Michael Küppers, Detlef Koschny, Marc Hofmann, M. A. Barucci, J. L. Bertaux, P. J. Gutierrez, Carsten Güttler, M. De Cecco, Nilda Oklay, R. Rodrigo, Jessica Agarwal, Giampiero Naletto, B. J. R. Davidsson, Esther Drolshagen, V. Da Deppo, N. Thomas, Cesare Barbieri, Philippe Lamy, Géza Kovács, Theresa Ott, Jakob Deller, Stubbe F. Hviid, Marco Fulle, Zhong-Yi Lin, J.-R. Kramm, Hans Rickman, Cecilia Tubiana, J-C. Lee, Monica Lazzarin, J. J. López-Moreno, Jean-Baptiste Vincent, Francesco Marzari, Jörg Knollenberg, Sonia Fornasier, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, Ekkehard Kührt, L. M. Lara, Stefano Debei, Gabriele Cremonese, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, 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), 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), 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), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Department of Physics and Astronomy [Uppsala], Uppsala University, 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), Department of Earth Sciences [Chung-Li City], Department of Information Engineering [Padova] (DEI), University of Oldenburg, Physikalisches Institut [Bern], Universität Bern [Bern], 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), 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), 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)-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: 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Comet, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrobiology, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, comets: individual: 67P/Churyumov–Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], 13. Climate action, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business
Abstract: Cometary outbursts on several comets have been observed both by ground-based telescopes and by in situ instruments on spacecraft. However, the mechanism behind these phenomena and their physical properties are still unclear. The optical, spectrocopic and infrared remote imaging system (OSIRIS) onboard the Rosetta spacecraft provided first-hand information on the outbursts from comet 67P/Churyumov-Gerasimenko during its perihelion passage in 2015. The physical properties of the outbursts can be investigated by examining the time series of these high-resolution images. An analysis is made of the wide- and narrow-angle images obtained during the monitoring of the outburst sequences, which occurred between July and September in 2015. A ring-masking technique is used to calculate the excess brightness of the outbursts. The ejected mass and expansion velocity of the outbursts is estimated from differences in images made with the same filter (orange filter). The calculated excess brightness from these outburst plumes ranges from a few per cent to 28 per cent. In some major outbursts, the brightness contribution from the outburst plume can be one or two times higher than that of the typical coma jet activities. The strongest event was the perihelion outburst detected just a few hours before perihelion. The mass ejection rate during a generic outburst could reach a few per cent of the steady-state value of the dust coma. Transient events are detected by studying the brightness slope of the outburst plume with continuous streams of outflowing gas and dust triggered by driving mechanisms, as yet not understood, which remain active for several minutes to less than a few hours.
Published: 2017

17. 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

18. 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

19. Waypoints for Opportunistic SmallSat/CubeSat Missions to Comets and Asteroids

Author: T. Hewagama, S. Aslam, M. F. A'Hearn, P. Clark, M. Daly, D. Folta, N. Gorius, T. Hurford, M. Keidar, T. Livengood, B. Malphrus, M. Mumma, C. Proulx, J. Sunshine, and G. Villanueva
Published: 2017
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20. The 67P/Churyumov-Gerasimenko observation campaign in support of the Rosetta mission

Author: Benoit Carry, M. F. A'Hearn, Sebastien Besse, Michaël Gillon, M. J. Mumma, Galin Borisov, B. Rajkumar, Janet E. Drew, Olga Muñoz, Viktor Afanasiev, Tarik Zegmott, Lucas Paganini, D. Bodewits, Rita Schulz, Emily Kramer, Adam J. McKay, Diane H. Wooden, J. de León, Michael Schmidt, Geraint H. Jones, S. Haque, Andrew McNeill, Fernando Moreno, Sara Faggi, P. J. Gutiérrez, Jérémie Lasue, Aurélie Guilbert-Lepoutre, J. M. Sunshine, Javier Licandro, Zhong-Yi Lin, Pedro Lacerda, Philippe Rousselot, Jose Luis Ortiz, Nicolas Biver, Marco Micheli, J. J. López-Moreno, Matthew M. Knight, Jon Marchant, Detlef Koschny, Dominik R. G. Schleicher, F. Aceituno, Michael S. P. Kelley, Colin Snodgrass, G. P. Tozzi, Michael A. DiSanti, Karen J. Meech, Olivier Hainaut, Alfredo Sota, Niklas J. T. Edberg, Edith Hadamcik, Rene Duffard, Rosita Kokotanekova, Erika L. Gibb, Damien Hutsemekers, E. Ramos, Y. Ramanjooloo, A. Guijarro, Ulrich Hopp, Luisa Lara, Stephen C. Lowry, Tim Lister, Anita L. Cochran, V. Casanova, Pablo Santos-Sanz, J. Kleyna, R. Hedrosa, M. Pajuelo, A. K. Sen, Cyrielle Opitom, Emmanuel Jehin, A. Thompson, Alan Fitzsimmons, Geronimo L. Villanueva, E. J. W. de Mooij, Stefano Bagnulo, C. Ries, Boncho P. Bonev, O. Ivanova, Amy Mainzer, John K. Davies, Blair C. Conn, Anny Chantal Levasseur-Regourd, P. Nikolov, Auni Somero, Nikolai Kiselev, Lori M. Feaga, Maria Monguió, Francisco J. Pozuelos, A. Stinson, M. Delacruz, Björn Davidsson, Jacqueline V. Keane, M. Kluge, Dean C. Hines, Simon F. Green, Jean Manfroid, James Bauer, Silvia Protopapa, M. de Val-Borro, T. Pursimo, Xiaobin Wang, Cecilia Tubiana, Hermann Boehnhardt, Masafumi Yagi, I. Mohammed, Vera Rosenbush, F. Hoyo, Harry Lehto, G. Bergond, B. Yang, Méabh Hyland, Arno Riffeser, Hideaki Fujiwara, Erin L. Ryan, B. Zaprudin, School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] ( OU ), Department of Astronomy [College Park], University of Maryland [College Park], Instituto de Astrofísica de Andalucía ( IAA ), Consejo Superior de Investigaciones Científicas [Spain] ( CSIC ), Special Astrophysical Observatory of the Russian Academy of Sciences ( SAO ), Russian Academy of Sciences [Moscow] ( RAS ), Armagh Observatory [Armagh], Jet Propulsion Laboratory ( JPL ), NASA-California Institute of Technology ( CALTECH ), Centro Astronómico Hispano Alemán, European Space Astronomy Center ( ESAC ), European Space Agency ( ESA ), 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 ), Department of Physics [Washington], American University Washington D.C. ( AU ), Institute of Astronomy and National Astronomical Observatory, Bulgarian Academy of Sciences, Joseph Louis LAGRANGE ( LAGRANGE ), Université Nice Sophia Antipolis ( UNS ), Université Côte d'Azur ( UCA ) -Université Côte d'Azur ( UCA ) -Observatoire de la Côte d'Azur, Université Côte d'Azur ( UCA ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Mécanique Céleste et de Calcul des Ephémérides ( IMCCE ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Lille-Centre National de la Recherche Scientifique ( CNRS ), McDonald Observatory, University of Texas at Austin [Austin], Research School of Astronomy and Astrophysics [Canberra] ( RSAA ), Australian National University ( ANU ), Gemini Observatory [Southern Operations Center], Association of Universities for Research in Astronomy ( AURA ), UK Astronomy Technology Centre ( UK ATC ), Science and Technology Facilities Council ( STFC ), Universidad de La Laguna ( ULL ), Instituto de Astrofisica de Canarias ( IAC ), Astrophysics Research Centre [Belfast] ( ARC ), Queen's University [Belfast] ( QUB ), Catholic University of America, Astrochemistry Laboratory [Greenbelt], NASA Goddard Space Flight Center ( GSFC ), Department of Astrophysical Sciences [Princeton], Princeton University, Institute for Astronomy [Honolulu], University of Hawaii at Manoa ( UHM ), School of Physics, Astronomy and Mathematics [Hatfield], University of Hertfordshire [Hatfield] ( UH ), Swedish Institute of Space Physics [Uppsala] ( IRF ), National Astronomical Observatory of Japan ( NAOJ ), Department of Physics and Astronomy [Columbia], University of Missouri-Columbia, Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules ( UTINAM ), Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université de Franche-Comté ( UFC ), IMPEC - 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 ), European Southern Observatory ( ESO ), Department of Physics [Trinidad], The University of the West Indies, Space Telescope Science Institute ( STSci ), Ludwig-Maximilians University [Munich] ( LMU ), Astronomical Institute of the Slovak Academy of Sciences, Slovak Academy of Science [Bratislava] ( SAS ), Mullard Space Science Laboratory ( MSSL ), University College of London [London] ( UCL ), Centre for Planetary Sciences [UCL/Birkbeck] ( CPS ), Main Astronomical Observatory of NAS of Ukraine ( MAO ), National Academy of Sciences of Ukraine ( NASU ), Research and Scientific Support Department, ESTEC ( RSSD ), European Space Research and Technology Centre ( ESTEC ), European Space Agency ( ESA ) -European Space Agency ( ESA ), 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 ), Tuorla Observatory, University of Turku, Institute of Astronomy [Taiwan] ( IANCU ), National Central University [Taiwan] ( NCU ), Las Cumbres Observatory ( LCO ), Centre for Astrophysics and Planetary Science [Canterbury] ( CAPS ), University of Kent [Canterbury], Astrophysics Research Institute [Liverpool] ( ARI ), Liverpool John Moores University ( LJMU ), ESA SSA-NEO Coordination Centre, Caribbean Institute of Astronomy ( CARINA ), Pontificia Universidad Católica del Perú ( PUCP ), Nordic Optical Telescope ( NOT ), SETI Institute, Lowell Observatory [Flagstaff], European Space Agency, Scientific Support Office, Assam University, INAF - Osservatorio Astrofisico di Arcetri ( OAA ), Istituto Nazionale di Astrofisica ( INAF ), Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences [Beijing] ( CAS ), Yunnan Observatories, Chinese Academy of Sciences [Changchun Branch] ( CAS ), NASA Ames Research Center ( ARC ), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), University of Maryland System-University of Maryland System, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Special Astrophysical Observatory of the Russian Academy of Sciences (SAO), Russian Academy of Sciences [Moscow] (RAS), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Centro Astronómico Hispano Alemán, Observatorio de Calar Alto (CAHA), European Space Astronomy Centre (ESAC), European Space Agency (ESA), 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, American University Washington D.C. (AU), Institute of Astronomy of the Bulgarian Academy of Sciences, Bulgarian Academy of Sciences (BAS), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-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), Research School of Astronomy and Astrophysics [Canberra] (RSAA), Australian National University (ANU), Association of Universities for Research in Astronomy (AURA), UK Astronomy Technology Centre (UK ATC), Science and Technology Facilities Council (STFC), Universidad de La Laguna [Tenerife - SP] (ULL), Instituto de Astrofisica de Canarias (IAC), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), NASA Goddard Space Flight Center (GSFC), University of Hawai‘i [Mānoa] (UHM), University of Hertfordshire [Hatfield] (UH), Swedish Institute of Space Physics [Uppsala] (IRF), National Astronomical Observatory of Japan (NAOJ), Department of Physics and Astronomy [Columbia] (Mizzou Physics), University of Missouri [Columbia] (Mizzou), University of Missouri System-University of Missouri System, Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), 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), European Southern Observatory (ESO), Space Telescope Science Institute (STSci), Ludwig-Maximilians-Universität München (LMU), Slovak Academy of Science [Bratislava] (SAS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Centre for Planetary Sciences [UCL/Birkbeck] (CPS), Main Astronomical Observatory of NAS of Ukraine (MAO), National Academy of Sciences of Ukraine (NASU), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), 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), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Las Cumbres Observatory (LCO), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), Astrophysics Research Institute [Liverpool] (ARI), Liverpool John Moores University (LJMU), Caribbean Institute of Astronomy (CARINA), Pontificia Universidad Católica del Perú (PUCP), Nordic Optical Telescope (NOT), ESA Scientific Support Office, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Chinese Academy of Sciences [Beijing] (CAS), Chinese Academy of Sciences [Changchun Branch] (CAS), NASA Ames Research Center (ARC), NASA-California Institute of Technology (CALTECH), Agence Spatiale Européenne = European Space Agency (ESA), Pôle Planétologie du LESIA, 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)-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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), 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), and Pontificia Universidad Católica del Perú = Pontifical Catholic University of Peru (PUCP)
Subjects: Future studies, History, 010504 meteorology & atmospheric sciences, General Mathematics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], General Physics and Astronomy, FOS: Physical sciences, Context (language use), 01 natural sciences, Astrobiology, Jupiter, 0103 physical sciences, 010303 astronomy & astrophysics, QC, 0105 earth and related environmental sciences, QB, Earth and Planetary Astrophysics (astro-ph.EP), comet 67P/Churyumov?Gerasimenko, Rosetta, solar system, observational astronomy, ta115, Spacecraft, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], General Engineering, Articles, [ SDU.ASTR.EP ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Early results, business, [ SDU.ASTR.SR ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Earth and Planetary Astrophysics
Abstract: We present a summary of the campaign of remote observations that supported the European Space Agency's Rosetta mission. Telescopes across the globe (and in space) followed comet 67P/Churyumov-Gerasimenko from before Rosetta's arrival until nearly the end of mission in September 2016. These provided essential data for mission planning, large-scale context information for the coma and tails beyond the spacecraft, and a way to directly compare 67P with other comets. The observations revealed 67P to be a relatively `well behaved' comet, typical of Jupiter family comets and with activity patterns that repeat from orbit-to-orbit. Comparison between this large collection of telescopic observations and the in situ results from Rosetta will allow us to better understand comet coma chemistry and structure. This work is just beginning as the mission ends -- in this paper we present a summary of the ground-based observations and early results, and point to many questions that will be addressed in future studies., Comment: Author prepared version; final published version available at journal. 22 pages
Published: 2017

21. 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

22. 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

23. 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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24. 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

25. 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

26. 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

27. The demise of Comet 85P/Boethin, the first EPOXI mission target

Author: J. Kleyna, Ignacio Ferrin, William T. Reach, James M. Bauer, Veronica Motta, J. Pittichová, Yanga R. Fernandez, David J. Osip, Steven R. Chesley, Tetsuharu Fuse, Karen J. Meech, M. J. Holman, Carey M. Lisse, Olivier Hainaut, P. Challis, Stephen C. Lowry, Eric Christensen, T. Brink, M. F. A'Hearn, Donald K. Yeomans, M. Mateo, and Amy Mainzer
Subjects: Physics, Very Large Telescope, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, Ephemeris, law.invention, Telescope, Spitzer Space Telescope, Space and Planetary Science, law, Observatory, Limiting magnitude, Subaru Telescope
Abstract: Comet 85P/Boethin was selected as the original comet target for the Deep Impact extended mission, EPOXI . Because this comet had been only observed at two apparitions in 1975 and 1986 and consequently had a large ephemeris error, an early intense recovery effort similar to that of 1P/Halley was undertaken beginning in 2005 using the ESO Very Large Telescopes (VLTs) in a distant comet program. These were challenging observations because of the low galactic latitude, and an error ellipse (the line of variations) that was larger than the CCD FOV, and the comet was not seen. Dedicated recovery observing time was awarded on the Subaru telescope in April and May 2006, and June 2007, in addition to time on the VLT and Canada–France–Hawaii telescopes during July–August 2007 with wide field mosaics and mosaicing techniques. The limiting V magnitudes from these observing runs ranged between 25.7 and 27.3 and again the comet was not seen in the individual nights. A new image processing technique was developed to stack images over extended runs and runs after distorting them to account for dilations and rotations in the line of variations using modifications of the world coordinate system. A candidate at V ∼ 27.3 was found in the CFHT data along the LOV, 2.5′ west of the nominal ephemeris position. The EPOXI mission was unwilling to re-target the spacecraft without a confirmation. Additional time was secured using the Spitzer Space Telescope, the Gemini South 8-m telescope, the Clay and Baade (Magellan 6.5 m), CTIO 4 m, and SOAR 4 m telescopes during 2007 September and October A composite image made by stacking the new data showed no plausible candidate nucleus to a limiting magnitude of V = 28.5, corresponding to a nucleus radius between 0.1 and 0.2 km (assuming an albedo of 0.04). The comet was declared lost, presumably having disintegrated. Searches in the WISE data set revealed no debris trail, but no constraints on the possible time of disruption can be made. NASA approved the trajectory correction maneuver to go to Comet 103P/Hartley 2 on 2007 November 1. Many observers searched for the comet as it came to its December 2008 perihelion, but no trace of the nucleus was found. Based on observations collected at the Very Large Telescope, Chile, in part on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan, in part using data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile, in part on observations obtained with MegaPrime/MegaCam, a joint project of CFHT and CEA/DAPNIA, at the Canada–France–Hawaii Telescope (CFHT) which is operated by the National Research Council (NRC) of Canada, the Institut National des Science de l’Univers of the Centre National de la Recherche Scientifique (CNRS) of France, and the University of Hawaii, in part using data collected at the Cerro Tololo Inter-American Observatory, National Optical Astronomy Observatory, which are operated by the Association for Research in Astronomy, under contract with the National Science Foundation, and in part on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministerio da Ciencia, Tecnologia, e Inovacao (MCTI) da Republica Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU). This work is also based in part on observations taken with the Spitzer Space Telescope, which is operated by JPL/Caltech under a contract with NASA.
Published: 2013

28. Return to Comet Tempel 1: Overview of Stardust-NExT results

Author: J. M. Sunshine, Peter C. Thomas, Jian-Yang Li, Robert W. Farquhar, S. Sackett, Aron A. Wolf, M. J. S. Belton, S. Bhaskaran, Olivier Groussin, Dennis Bodewits, J. Veverka, Kenneth P. Klaasen, Tony L. Farnham, Simon F. Green, Brian Carcich, Thanasis E. Economou, Jochen Kissel, Alan W. Harris, M. F. A'Hearn, A. Cheuvront, Jay Melosh, Donald E. Brownlee, S. R. Chesley, Peter H. Schultz, Dennis D. Wellnitz, Johan Silen, Karen J. Meech, James E. Richardson, B. C. Clark, 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: [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, Accretion (meteorology), Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, Radius, Albedo, Fault scarp, 01 natural sciences, medicine.anatomical_structure, Impact crater, 13. Climate action, Space and Planetary Science, Geometric albedo, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, Nucleus, Geology, 0105 earth and related environmental sciences
Abstract: International audience; On February 14, 2011 Stardust-NExT (SN) flew by Comet Tempel 1, the target of the Deep Impact (DI) mission in 2005, obtaining dust measurements and high-resolution images of areas surrounding the 2005 impact site, and extending image coverage to almost two thirds of the nucleus surface. The nucleus has an average radius of 2.83 +/- 0.1 km and a uniform geometric albedo of about 6% at visible wavelengths. Local elevation differences on the nucleus reach up to 830 m. At the time of encounter the spin rate was 213 degrees per day (period = 40.6 h) and the comet was producing some 130 kg of dust per second. Some 30% of the nucleus is covered by smooth flow-like deposits and related materials, restricted to gravitational lows. This distribution is consistent with the view that the smooth areas represent material erupted from the subsurface and date from a time after the nucleus achieved its current shape. It is possible that some of these eruptions occurred after 1609 when the comet's perihelion distance decreased from 3.5 AU to the current 1.5 AU. Much of the surface displays evidence of layering: some related to the smooth flows and some possibly dating back to the accretion of the nucleus. Pitted terrain covers approximately half the nucleus surface. The pits range up to 850 m in diameter. Due to their large number, they are unlikely to be impact scars: rather they probably result from volatile outbursts and sublimational erosion. The DI impact site shows a subdued depression some 50 m in diameter implying surface properties similar to those of dry, loose snow. It is possible that the 50-m depression is all that remains of an initially larger crater. In the region of overlapping DI and SN coverage most of the surface remained unchanged between 2005 and 2011 in albedo, photometric properties and morphology. Significant changes took place only along the edges of a prominent smooth flow estimated to be 10-15 m thick, the margins of which receded in places by up to 50 m. Coma and jet activity were lower in 2011 than in 2005. Most of the jets observed during the SN flyby can be traced back to an apparently eroding terraced scarp. The dust instruments detected bursts of impacts consistent with a process by which larger aggregates of material emitted from the nucleus subsequently fragment into smaller particles within the coma. (c) 2012 Elsevier Inc. All rights reserved.
Published: 2013

29. Surface geomorphology of Jupiter Family Comets: A geologic process perspective

Author: Andrew F. Cheng, M. F. A'Hearn, and Carey M. Lisse
Subjects: Jupiter, Impact crater, Space and Planetary Science, Erosion, Aeolian processes, Flux, Astronomy and Astrophysics, Outflow, Mars Exploration Program, Layering, Geology, Astrobiology
Abstract: Recent spacecraft encounters with Jupiter Family Comets have revealed markedly diverse surface morphologies: Wild 2 is dominated by steep-walled and flat-floored depressions, Tempel 1 is relatively smooth and exhibits evidence for flows and layering, while Hartley 2 is bi-lobed with knobby terrain at its ends and a much smoother terrain in its middle. This diversity of surface morphologies has been interpreted as an evolutionary sequence (Belton, M.J.S. [2010]. Icarus 210, 881–897) where Jupiter Family Comets evolve from Wild 2 morphology, then to Tempel 1 morphology, and finally to Hartley 2 morphology. We propose instead that the diversity of surface morphology reflects geologic processing with diverse outcomes. In addition to impact cratering, we consider surface modification driven by the cometary activity which is responsible for gas and dust production. We consider eolian erosion that may be driven by the outflow of cometary vapor, making use of information from wind tunnel experiments and in situ studies of eolian erosion on Mars. We adopt the model of van der Waals cohesion recently proposed by Scheeres et al. (Scheeres, D., Hartzell, C., Sanchez, P., Swift, M. [2010]. Icarus 210, 968–984) and find that the average CO 2 vapor outflow flux at Hartley 2 of 0.95 × 10 17 cm −2 s −1 implies wind speeds sufficient to mobilize particles of 10 cm size even close to the icy reservoirs where the vapor is evolved, below the surface. We suggest that particles are mobilized and entrained in flows within sub-surface outflow channels, emerging to be readily lifted into the coma, and fragmenting in the process. Although water production from Hartley 2 is greater, most of it is evolved in the coma from icy particles and does not contribute to eolian erosion of the nucleus. On the other hand, the much lower vapor outflow flux at Tempel 1 of 4 × 10 14 cm −2 s −1 is insufficient, in the present model, to mobilize particles but is consistent with generating repeated fluidization episodes. The Wild 2 case is intermediate, with average outflow flux 7 × 10 16 cm −2 s −1 which would be, in our model, sufficient to support eolian erosion. The steep-walled, flat-floor depressions on Wild 2 may have originated as impact features but have been subsequently modified by eolian erosion causing slope recession. We do not have definitive evidence to discriminate between an evolutionary sequence and diverse geologic outcomes, but we suggest future in situ observations at comets that may do so.
Published: 2013

30. The 2016 Feb 19 outburst of comet 67P/CG: an ESA Rosetta multi-instrument study

Author: Andrew J. Steffl, Harold A. Weaver, Lori M. Feaga, Paul R. Weissman, B. J. R. Davidsson, Francesco Marzari, Chia-Yu Tzou, Roberto Sordini, J. L. Bertaux, Philippe Lamy, Michaël Gillon, Hans Rickman, P. Yanamandra-Fisher, Matthew M. Knight, O. Mousis, Nicolas Altobelli, Sonia Fornasier, Jessica Agarwal, Marco Fulle, Marina Galand, A. I. Erikson, J. J. López-Moreno, Eric Schindhelm, Mihaly Horanyi, Charlotte Götz, James L. Burch, Giampiero Naletto, Kathrin Altwegg, E. Mazzotta Epifani, Jean Manfroid, Mark Bentley, Jörg Knollenberg, Emmanuel Jehin, Ekkehard Kührt, M Muller, M. A. Barucci, Cesare Barbieri, Pierre Henri, V. Della Corte, P. J. Gutiérrez, Stavro Ivanovski, Carsten Güttler, Harald Krüger, Ralf Srama, Cecilia Tubiana, Rafael Rodrigo, F. Schmidt, J. E. Rodriguez, Vladimir Zakharov, J.-R. Kramm, Roland Schmied, S. A. Stern, Eberhard Grün, Thurid Mannel, Jakob Deller, A. Gicquel, Colin Snodgrass, Bernhard Geiger, M. De Cecco, B. Grieger, Monica Lazzarin, Seungwon Lee, Wing-Huen Ip, Laurent Jorda, Holger Sierks, Stubbe F. Hviid, Marc Hofmann, Paul D. Feldman, J. Wm. Parker, M. Sommer, Michael Küppers, Matthew Taylor, M. F. A'Hearn, Olivier Groussin, Simon F. Green, Detlef Koschny, Nicolas Thomas, Horst Uwe Keller, Cyrielle Opitom, Gabriele Cremonese, Niklas J. T. Edberg, Mark Hofstadter, R. H. Soja, M. Ferrari, E. Morales, Ivano Bertini, N. Biver, Pasquale Palumbo, Nilda Oklay, Stefano Debei, V. Da Deppo, L. M. Lara, Luigi Colangeli, Alessandra Rotundi, Xian Shi, J. B. Vincent, Science and Technology Facilities Council (STFC), 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 Kernphysik (MPIK), Max-Planck-Gesellschaft, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), 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), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Swedish Institute of Space Physics [Uppsala] (IRF), Department of Physics and Astronomy [Baltimore], Johns Hopkins University (JHU), Imperial College London, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Jaicoa Observatory, 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), European Space Operations Center (ESOC), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Institute of Physics [Graz], Karl-Franzens-Universität Graz, Institut für Raumfahrtsysteme (IRS), Universität Stuttgart [Stuttgart], School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Space Science Institute [Boulder] (SSI), 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)-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), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), European Space Research and Technology Centre (ESTEC), INAF - Osservatorio Astronomico di Padova (OAPD), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Physics and Astronomy [Uppsala], Uppsala University, 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 Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), INAF - Osservatorio Astronomico di Roma (OAR), Department of Information Engineering [Padova] (DEI), SwRI Planetary Science Directorate [Boulder], Southwest Research Institute [Boulder] (SwRI), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), International Space Science Institute [Bern] (ISSI), Department of Space Studies [Boulder], Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Planetary Science Institute [Tucson] (PSI), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Agence Nationale de la Recherche (ANR), ANR-15-CE31-0009,SPECTRA,Sonder le Plasma dans l'Environnement d'une ComètE avec RosettA(2015), ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011), Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), Universität Bern [Bern], 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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES), 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 Napoli 'Parthenope' [Napoli], Karl-Franzens-Universität [Graz, Autriche], Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), 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)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), ITA, USA, GBR, FRA, DEU, and ESP
Subjects: 67P/Churyumov-Gerasimenko, Brightness, Electron density, 010504 meteorology & atmospheric sciences, 530 Physics, 67P/Churyumov-gerasimenko, Comets, Individual, Astronomy and Astrophysics, Space and Planetary Science, Comet, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, 7. Clean energy, law.invention, Astronomi, astrofysik och kosmologi, law, Dust collector, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Spectrometer, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy, comets: individual: 67P/Churyumov-Gerasimenko, Radius, 620 Engineering, Wavelength, 0201 Astronomical And Space Sciences, 13. Climate action, Magnitude (astronomy), individual: 67P/Churyumov-Gerasimenko [comets]
Abstract: On 2016 Feb 19, nine Rosetta instruments serendipitously observed an outburst of gas and dust from the nucleus of comet 67P/Churyumov-Gerasimenko. Among these instruments were cameras and spectrometers ranging from UV over visible to microwave wavelengths, in situ gas, dust and plasma instruments, and one dust collector. At 09:40 a dust cloud developed at the edge of an image in the shadowed region of the nucleus. Over the next two hours the instruments recorded a signature of the outburst that significantly exceeded the background. The enhancement ranged from 50 per cent of the neutral gas density at Rosetta to factors >100 of the brightness of the coma near the nucleus. Dust related phenomena (dust counts or brightness due to illuminated dust) showed the strongest enhancements (factors>10). However, even the electron density at Rosetta increased by a factor 3 and consequently the spacecraft potential changed from ~-16 V to -20 V during the outburst. A clear sequence of events was observed at the distance of Rosetta (34 km from the nucleus): within 15 min the Star Tracker camera detected fast particles (~25 m s-1) while 100 ¿m radius particles were detected by the GIADA dust instrument ~1 h later at a speed of 6 m s-1. The slowest were individual mm to cm sized grains observed by the OSIRIS cameras. Although the outburst originated just outside the FOV of the instruments, the source region and the magnitude of the outburst could be determined. © 2016 The Authors., 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. We thank all elements of the Rosetta project for the magnificent job they are doing to make this mission an astounding success. The Alice team acknowledges continuing support from NASA's Jet Propulsion Laboratory through contract 1336850. GIADA/Univ Parthenope NA/INAFOAC/IAA/INAF-IAPS: this research was supported by the Italian Space Agency (ASI) within the ASI-INAF agreements I/032/05/0 and I/024/12/0. OSIRIS was built by a consortium of the Max-Planck- Institut für Sonnensystemforschung, Göttingen, Germany, CISAS University of Padova, Italy, the Laboratoire d'Astrophysique de Marseille, France, the Instituto de Astrofìsica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Técnica Aeroespacial, Madrid, Spain, the Universidad Politéechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, the UK(STFC), and the Institut für Datentechnik und Kommunikationsnetze der Technischen Universität 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. Work at LPC2E/CNRS was supported by CNES and by ANR under the financial agreement ANR-15-CE31-0009-01. Work on ROSINA COPS at the University of Bern was funded by the State of Bern, the Swiss National Science Foundation and by the European Space Agency PRODEX program. OM: this work has been partly carried out thanks to the support of the A*MIDEX project (no ANR-11-IDEX-0001-02) funded by the ‘Investissements d'Avenir’ French Government program, managed by the French National Research Agency (ANR). This work also benefited from the support of CNRS-INSU national program for planetology (PNP).
Published: 2016

31. Evolution of the Dust Size Distribution of Comet 67P/Churyumov–Gerasimenko from 2.2 au to Perihelion

Author: B. J. R. Davidsson, Nicolas Altobelli, Philippe Lamy, J. E. Rodriguez, Vladimir Zakharov, A. Molina, F. Lucarelli, Ivano Bertini, Ekkehard Kührt, R. Kramm, Bo Å. S. Gustafson, P. Weissman, Jose Luis Ortiz, Michael Küppers, Roberto Sordini, J. L. Bertaux, A. Lopez-Jimenez, Pasquale Palumbo, Alessandra Rotundi, J. J. López-Moreno, P. J. Gutiérrez, Mark Leese, Hans Rickman, J. M. Jeronimo, M. A. Barucci, E. Mazzotta Epifani, Monica Lazzarin, Jean-François Crifo, Stavro Ivanovski, Detlef Koschny, Nicolas Thomas, Vito Mennella, Eberhard Grün, Holger Sierks, Nilda Oklay, Carsten Güttler, M. De Cecco, K. P. Wenzel, Cesare Barbieri, F. Moreno, Stefano Mottola, Simon F. Green, Stubbe F. Hviid, Jean-Baptiste Vincent, Wing-Huen Ip, Laurent Jorda, Luisa Lara, V. Da Deppo, John C. Zarnecki, Mario Accolla, E. Bussoletti, Francesca Esposito, Francesco Marzari, M. L. Herranz, Sonia Fornasier, Jean-Marie Perrin, Luigi Colangeli, Jessica Agarwal, F. Giovane, M. Ferrari, Ernesto Palomba, Cecilia Tubiana, Giampiero Naletto, Marco Fulle, J. A. M. McDonnell, Dennis Bodewits, Jörg Knollenberg, V. Della Corte, Rafael Rodrigo, R. Morales, M. F. A'Hearn, Olivier Groussin, Horst Uwe Keller, F. J. M. Rietmeijer, M. Cosi, Stefano Debei, Gabriele Cremonese, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Universita degli studi di Napoli 'Parthenope' [Napoli], 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), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), 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 (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), INAF - Osservatorio Astrofisico di Catania (OACT), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, European Space Astronomy Centre (ESAC), European Space Agency (ESA), IMPEC - 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), Selex-ES, INAF - Osservatorio Astronomico di Padova (OAPD), HEPPI - LATMOS, 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 Capodimonte (OAC), Virginia Polytechnic Institute and State University [Blacksburg], University of Florida [Gainesville], School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), Max-Planck-Institut für Kernphysik (MPIK), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), INAF - Osservatorio Astronomico di Roma (OAR), University of Kent [Canterbury], Departamento de Fisica Aplicada [Granada], Universidad de Granada (UGR), Department of Information Engineering [Padova] (DEI), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut de Recherche pour le Développement (IRD), Department of Earth and Planetary Sciences [Albuquerque] (EPS), The University of New Mexico [Albuquerque], Physikalisches Institut [Bern], Universität Bern [Bern], Planetary Science Institute [Tucson] (PSI), Università degli Studi di Padova = University of Padua (Unipd), 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), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), 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), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA), PLANETO - LATMOS, HELIOS - LATMOS, National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Florida [Gainesville] (UF), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Universidad de Granada = University of Granada (UGR), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Centre National de la Recherche Scientifique (CNRS), Universität Bern [Bern] (UNIBE), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: instruments [space vehicles], 010504 meteorology & atmospheric sciences, 530 Physics, Comet dust, Comet, Flux, comets: individual (67P/Churyumov-Gerasimenko), general, space vehicles: instruments, Astronomy and Astrophysics, Space and Planetary Science [comets], Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, GIADA, 01 natural sciences, general [comets], law.invention, Orbiter, Interplanetary dust cloud, law, Dust collector, Rosetta, 0103 physical sciences, Nadir, comets: general, Space and Planetary Science, OSIRIS, individual (67P/Churyumov-Gerasimenko) [comets], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], 520 Astronomy, Astronomy, Mass ratio, 620 Engineering, comet 67P/Churyumov–Gerasimenko, 13. Climate action, Astrophysics::Earth and Planetary Astrophysics
Abstract: The Rosetta probe, orbiting Jupiter-family comet 67P/Churyumov–Gerasimenko, has been detecting individual dust particles of mass larger than 10^(−10) kg by means of the GIADA dust collector and the OSIRIS Wide Angle Camera and Narrow Angle Camera since 2014 August and will continue until 2016 September. Detections of single dust particles allow us to estimate the anisotropic dust flux from 67P, infer the dust loss rate and size\ud distribution at the surface of the sunlit nucleus, and see whether the dust size distribution of 67P evolves in time.\ud The velocity of the Rosetta orbiter, relative to 67P, is much lower than the dust velocity measured by GIADA, thus\ud dust counts when GIADA is nadir-pointing will directly provide the dust flux. In OSIRIS observations, the dust\ud flux is derived from the measurement of the dust space density close to the spacecraft. Under the assumption of radial expansion of the dust, observations in the nadir direction provide the distance of the particles by measuring\ud their trail length, with a parallax baseline determined by the motion of the spacecraft. The dust size distribution at\ud sizes >1 mm observed by OSIRIS is consistent with a differential power index of −4, which was derived from\ud models of 67P’s trail. At sizes
Published: 2016

32. The dust environment of comet 67P/Churyumov-Gerasimenko from Rosetta OSIRIS/GIADA and VLT observations in the 4.5 to 2.9 AU heliocentric distance range inbound

Author: M. F. A'Hearn, Sebastien Besse, Horst Uwe Keller, M. De Cecco, Alan Fitzsimmons, Emmanuel Jehin, Stefano Debei, Giampiero Naletto, Olivier Hainaut, R. Rodrigo, Francesco Marzari, Carsten Guettler, Géza Kovács, Dennis Bodewits, Olivier Groussin, J. Agarwal, Wing-Huen Ip, Laurent Jorda, Hans Rickman, Detlef Koschny, G. P. Tozzi, N. Oklay, L. M. Lara, V. Della Corte, Colin Snodgrass, F. Moreno, Nicolas Thomas, Jörg Knollenberg, Maurizio Pajola, P. Gutiérrez Marqués, Stubbe F. Hviid, G. Cremonese, Sara Faggi, J. J. Lopez Moreno, Francesca Ferri, B. J. R. Davidsson, E. Kuehrt, J. L. Bertaux, V. Da Deppo, Stefano Mottola, S. Fornasier, J.-R. Kramm, Holger Sierks, J. B. Vincent, Cecilia Tubiana, Monica Lazzarin, Ivano Bertini, P. L. Lamy, Marco Fulle, Cesare Barbieri, P. J. Gutierrez, Michael Kueppers, C. Opitom, M. A. Barucci, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), European Southern Observatory (ESO), 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 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'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), Department of Physics and Astronomy [Uppsala], Uppsala University, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Gauss Professor 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), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science, National Central University, Operations Department (ESAC), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), INAF - Osservatorio Astrofisico di Arcetri (OAA), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, ITA, USA, GBR, FRA, DEU, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Universität Bern [Bern], 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), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Monte Carlo method, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Coma (optics), Astrophysics, 01 natural sciences, Photometry, Methods: data analysis, 0103 physical sciences, Range (statistics), Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Physics, comets: individual: 67P/Churyumov-Gerasimenko / methods: data analysis / techniques: photometric, Very Large Telescope, Spacecraft, biology, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Mass ratio, biology.organism_classification, 13. Climate action, Space and Planetary Science, astro-ph.EP, Techniques: photometric, Osiris, business, Astrophysics - Earth and Planetary Astrophysics
Abstract: The ESA Rosetta spacecraft, currently orbiting around comet 67P, has already provided in situ measurements of the dust grain properties from several instruments, particularly OSIRIS and GIADA. We propose adding value to those measurements by combining them with ground-based observations of the dust tail to monitor the overall, time-dependent dust-production rate and size distribution. To constrain the dust grain properties, we take Rosetta OSIRIS and GIADA results into account, and combine OSIRIS data during the approach phase (from late April to early June 2014) with a large data set of ground-based images that were acquired with the ESO Very Large Telescope (VLT) from February to November 2014. A Monte Carlo dust tail code has been applied to retrieve the dust parameters. Key properties of the grains (density, velocity, and size distribution) were obtained from Rosetta observations: these parameters were used as input of the code to considerably reduce the number of free parameters. In this way, the overall dust mass-loss rate and its dependence on the heliocentric distance could be obtained accurately. The dust parameters derived from the inner coma measurements by OSIRIS and GIADA and from distant imaging using VLT data are consistent, except for the power index of the size-distribution function, which is $\alpha$=--3, instead of $\alpha$=--2, for grains smaller than 1 mm. This is possibly linked to the presence of fluffy aggregates in the coma. The onset of cometary activity occurs at approximately 4.3 au, with a dust production rate of 0.5 kg/s, increasing up to 15 kg/s at 2.9 au. This implies a dust-to-gas mass ratio varying between 3.8 and 6.5 for the best-fit model when combined with water-production rates from the MIRO experiment., Comment: Accepted by Astronomy and Astrophysics (January 17th, 2016)
Published: 2016

33. Observations and analysis of a curved jet in the coma of comet 67P/Churyumov-Gerasimenko

Author: Jörg Knollenberg, Monica Lazzarin, M. F. A'Hearn, Michael Küppers, Jong-Shinn Wu, J.-C. Lee, Ivano Bertini, M. A. Barucci, Wing-Huen Ip, Laurent Jorda, L. M. Lara, P. L. Lamy, Horst Uwe Keller, G. Cremonese, Agata Rozek, Cesare Barbieri, Maurizio Pajola, Nicolas Thomas, J. J. Lopez-Moreno, C. C. Su, J.-R. Kramm, S. Debet, M. De Cecco, Cecilia Tubiana, Giampiero Naletto, F. La Forgia, S. Fornasier, Ekkehard Kührt, Stefano Mottola, I. L. Lai, Francesco Marzari, J. Agarwal, Detlef Koschny, Zhong-Yi Lin, Stubbe F. Hviid, C. Güttler, V. Da Deppo, Géza Kovács, Stephen C. Lowry, R. Rodrigo, Hans Rickman, Marco Fulle, P. J. Gutierrez, Olivier Groussin, Dennis Bodewits, Harald Michalik, J. L. Bertaux, B. J. R. Davidsson, Holger Sierks, N. Oklay, J. B. Vincent, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institute of Space Science [Taiwan], Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Department of Atmospheric Sciences [Taoyuan City], 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 di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), 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), 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), 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), 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 Physics and Astronomy [Uppsala], Uppsala University, Department of Industrial Engineering [Padova], University of Trento [Trento], 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'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Department of Information Engineering, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), National funding agencies of Germany (DLR), France (CNES), Italy (Agenzia Spaziale Italiana), Spain (Ministerio de Educación, Cultura y Deporte), Sweden (Swedish National Space Board), ESA, Ministry of Science and Technology of Taiwan, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA), Universität Bern [Bern], Ministerio de Educación, Cultura y Deporte (España), Swedish National Space Board, European Space Agency, Agenzia Spaziale Italiana, Centre National D'Etudes Spatiales (France), German Centre for Air and Space Travel, National Science and Technology Development Agency (Thailand), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, Gravity (chemistry), 010504 meteorology & atmospheric sciences, Terminal velocity, 530 Physics, Comet, Equator, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Coma (optics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, medicine, comets, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Jet (fluid), 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, 620 Engineering, medicine.anatomical_structure, Drag, Astrophysics::Earth and Planetary Astrophysics, Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. We analyze the physical properties and dynamical origin of a curved jet of comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus rotations starting on May 30 and persisting until early August, 2015. Methods. We simulated the motion of dust grains ejected from the nucleus surface under the influence of the gravity and viscous drag effect of the expanding gas flow from the rotating nucleus. Results. The formation of the curved jet is a combination of the size of the dust particles (∼0.1-1 mm) and the location of the source region near the nucleus equator. This enhances the spiral feature of the collimated dust stream after the dust is accelerated to a terminal speed on the order of m s. © ESO, 2016., The support of the national funding agencies of Germany (Deutschen Zentrums fur Luft- und Raumfahrt), France (Centre National d'Etudes Spatiales), Italy (Agenzia Spaziale Italiana), Spain (Ministerio de Educacion, Cultura y Deporte), Sweden (Swedish National Space Board; grant no. 74/10:2), and the ESA Technical Directorate is gratefully acknowledged. This work was also supported by grant number NSC 102-2112-M-008-013-MY3 and MOST 104-2119-M-008-024 from the Ministry of Science and Technology of Taiwan. We are indebted to the whole Rosetta mission team, Science Ground Segment, and Rosetta Mission Operation Control for their hard work making this mission possible.
Published: 2016

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

Author: Ivano Bertini, M. De Cecco, M. F. A'Hearn, J.-C. Lee, Dennis Bodewits, Monica Lazzarin, Wing-Huen Ip, Laurent Jorda, N. Oklay, F. Preusker, Sebastien Besse, H. U. Keller, Marco Fulle, Stefano Debei, F. Marzari, J. J. Lopez Moreno, Björn Davidsson, Lorenza Giacomini, Holger Sierks, Cecilia Tubiana, Michael Küppers, M. A. Barucci, Sonia Fornasier, Jean-Loup Bertaux, F. Scholten, P. J. Gutiérrez, Ekkehard Kührt, L. M. Lara, Philippe Lamy, Olivier Groussin, J. B. Vincent, A. Gracia-Berná, J.-R. Kramm, Jörg Knollenberg, Géza Kovács, Nicolas Thomas, Antoine Pommerol, A. T. Auger, Matteo Massironi, Carsten Güttler, Stubbe F. Hviid, Giampiero Naletto, V. Da Deppo, Maurizio Pajola, Gabriele Cremonese, Simone Marchi, Raphael Marschall, Detlef Koschny, Mohamed Ramy El-Maarry, R. Rodrigo, Hans Rickman, Cesare Barbieri, 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), National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], 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, 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), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Physics and Astronomy [Uppsala], Uppsala University, International Space Science Institute [Bern] (ISSI), 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)), 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)-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 Istituto di Fotonica e Nanotecnologie [Padova] (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), 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), INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Department of Information Engineering [Padova] (DEI), Agenzia Spaziale Italiana, Centre National D'Etudes Spatiales (France), Ministerio de Educación, Cultura y Deporte (España), Swedish National Space Board, European Space Agency, and German Centre for Air and Space Travel
Subjects: Surface (mathematics), 67P/Churyumov-Gerasimenko, Morphology (linguistics), 010504 meteorology & atmospheric sciences, 530 Physics, Comet, Terrain, Astrophysics, 01 natural sciences, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: observational, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, observational [Methods], Astronomy and Astrophysics, Space and Planetary Science, comets, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Physics, biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Northern Hemisphere, general [Comets], biology.organism_classification, 620 Engineering, On board, comets: general / comets: individual: 67P/Churyumov-Gerasimenko / methods: observational, [SDU]Sciences of the Universe [physics], Osiris, methods: observational
Abstract: Aims. The OSIRIS camera on board the Rosetta spacecraft has been acquiring images of the comet 67P/Churyumov-Gerasimenko (67P)'s nucleus since August 2014. Starting in May 2015, the southern hemisphere gradually became illuminated and was imaged for the first time. Here we present the regional morphology of the southern hemisphere, which serves as a companion to an earlier paper that presented the regional morphology of the northern hemisphere. Methods. We used OSIRIS images that were acquired at orbits ~45-125 km from the center of the comet (corresponding to spatial resolutions of ~0.8 to 2.3 m/pixel) coupled with the use of digital terrain models to define the different regions on the surface, and identify structural boundaries accurately. Results. Seven regions have been defined in the southern hemisphere bringing the total number of defined regions on the surface of the nucleus to 26. These classifications are mainly based on morphological and/or topographic boundaries. The southern hemisphere shows a remarkable dichotomy with its northern counterpart mainly because of the absence of wide-scale smooth terrains, dust coatings and large unambiguous depressions. As a result, the southern hemisphere closely resembles previously identified consolidated regions. An assessment of the overall morphology of comet 67P suggests that the comet's two lobes show surface heterogeneities manifested in different physical/mechanical characteristics, possibly extending to local (i.e., within a single region) scales.© 2016 ESO., 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

35. Summer fireworks on comet 67P

Author: Cesare Barbieri, Sebastien Besse, Jakob Deller, Zhong-Yi Lin, Francesco Marzari, Giampiero Naletto, Gabriele Cremonese, I. Toth, Xian Shi, Mohamed Ramy El-Maarry, Hans Rickman, Wing-Huen Ip, Laurent Jorda, Björn Davidsson, Ekkehard Kührt, Nilda Oklay, Holger Sierks, Sonia Fornasier, L. M. Lara, Cecilia Tubiana, V. Da Deppo, Marc Hofmann, Monica Lazzarin, Géza Kovács, Michael Küppers, P. Gutiérrez-Marquez, P. J. Gutiérrez, Jean-Baptiste Vincent, M. De Cecco, Ivano Bertini, F. Scholten, J.-R. Kramm, M. A. Barucci, Stefano Debei, Maurizio Pajola, Detlef Koschny, Nicolas Thomas, Jörg Knollenberg, J. J. Lopez Moreno, Matteo Massironi, S. Höfner, Rafael Rodrigo, F. Preusker, Stubbe F. Hviid, Philippe Lamy, Jessica Agarwal, A. Gicquel, Stefano Mottola, Marco Fulle, M. F. A'Hearn, H. U. Keller, Olivier Groussin, J. L. Bertaux, Carsten Güttler, Dennis Bodewits, 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, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Physikalisches Institut [Bern], Universität Bern [Bern], NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, 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), 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), 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), 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], Department of Information Engineering [Padova] (DEI), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Dipartimento di Geoscienze [Padova], Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Universität Bern [Bern] (UNIBE), 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), German Centre for Air and Space Travel, Centre National de la Recherche Scientifique (France), European Space Agency, Ministerio de Economía y Competitividad (España), Swedish National Space Board, Agenzia Spaziale Italiana, ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, 530 Physics, Comet dust, Comet, FOS: Physical sciences, Individual, Astrophysics, Noon, Fault scarp, Spatial distribution, 01 natural sciences, Astronomi, astrofysik och kosmologi, 0103 physical sciences, Comets, Astronomy, Astrophysics and Cosmology, Variation (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Morning, Gerasimenko, Earth and Planetary Astrophysics (astro-ph.EP), Physics, comets: individual: 67P/Churyumov–Gerasimenko, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy, Astronomy and Astrophysics, 620 Engineering, Plume, 13. Climate action, Space and Planetary Science, comets: individual: 67P/Churyumov, comets: individual: 67P: Churyumov Gerasimenko, individual: 67P/Churyumov-Gerasimenko [comets], Astrophysics - Earth and Planetary Astrophysics
Abstract: During its 2 yr mission around comet 67P/Churyumov¿Gerasimenko, ESA¿s Rosetta spacecraft had the unique opportunity to follow closely a comet in the most active part of its orbit. Many studies have presented the typical features associated with the activity of the nucleus, such as localized dust and gas jets. Here,we report on series ofmore energetic transient events observed during the 3 months surrounding the comet¿s perihelion passage in 2015 August.We detected and characterized 34 outbursts with the Rosetta cameras, one every 2.4 nucleus rotations. We identified three main dust plume morphologies associated with these events: a narrow jet, a broad fan, and more complex plumes featuring both previous types together. These plumes are comparable in scale and temporal variation to what has been observed on other comets. We present a map of the outbursts¿ source locations, and discuss the associated topography. We find that the spatial distribution sources on the nucleus correlate well with morphological region boundaries, especially in areas marked by steep scarps or cliffs. Outbursts occur either in the early morning or shortly after the local noon, indicating two potential processes: morning outbursts may be triggered by thermal stresses linked to the rapid change of temperature; afternoon events are most likely related to the diurnal or seasonal heat wave reaching volatiles buried under the first surface layer. In addition, we propose that some events can be the result of a completely different mechanism, in which most of the dust is released upon the collapse of a cliff. © 2016 The Authors., 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.
Published: 2016

36. Physical properties and dynamical relation of the circular depressions on comet 67P/Churyumov-Gerasimenko

Author: M. F. A'Hearn, Carsten Güttler, F. La Forgia, Olivier Groussin, J.-C. Lee, I. L. Lai, Nilda Oklay, Steve Boudreault, Francesco Marzari, Sebastien Besse, P. J. Gutiérrez, Giampiero Naletto, Holger Sierks, Björn Davidsson, V. Da Deppo, Marco Fulle, Cecilia Tubiana, Philippe Lamy, Detlef Koschny, J.-R. Kramm, Nicolas Thomas, H. U. Keller, Sonia Fornasier, Stefano Debei, M. De Cecco, J. J. López-Moreno, Monica Lazzarin, Jörg Knollenberg, Michael Küppers, Ekkehard Kührt, Y.-C. Cheng, Simone Marchi, Géza Kovács, L. M. Lara, Harald Michalik, Mohamed Ramy El-Maarry, Wing-Huen Ip, Jessica Agarwal, Laurent Jorda, Hans Rickman, Y. Li, J. B. Vincent, Stubbe F. Hviid, Stefano Mottola, M. A. Barucci, Maurizio Pajola, Cesare Barbieri, Stephen C. Lowry, J. L. Bertaux, E. Toth, Ivano Bertini, Gabriele Cremonese, Zhong-Yi Lin, R. Rodrigo, Dennis Bodewits, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], Department of Atmospheric Sciences [Taoyuan City], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, 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'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), 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), 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), 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), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), 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), Ministerio de Educación, Cultura y Deporte (España), Swedish National Space Board, European Space Agency, Agenzia Spaziale Italiana, Centre National D'Etudes Spatiales (France), German Centre for Air and Space Travel, Ministry of Science and Technology (Taiwan), ITA, USA, GBR, FRA, DEU, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), 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: Insolation, 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Comet, Astrophysics, 01 natural sciences, Asymmetry, symbols.namesake, individual: 67P/Churyumov-Gerasimenko [Comets], Comet nucleus, 0103 physical sciences, Size frequency, Pareto distribution, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Astronomy, comets: individual: 67P/Churyumov-Gerasimenko, 13. Climate action, Global distribution, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Aims. We aim to characterize the circular depressions of comet 67P/Churyumov-Gerasimenko and investigate whether such surface morphology of a comet nucleus is related to the cumulative sublimation effect since becoming a Jupiter family comet (JFC). Methods. The images from the Rosetta/OSIRIS science camera experiment are used to construct size frequency distributions of the circular depression structures on comet 67P and they are compared with those of the JFCs 81P/Wild 2, 9P/Tempel 1, and 103P/Hartley 2. The orbital evolutionary histories of these comets over the past 100 000 yr are analyzed statistically and compared with each other. Results. The global distribution of the circular depressions over the surface of 67P is charted and classified. Descriptions are given to the characteristics and cumulative size frequency distribution of the identified features. Orbital statistics of the JFCs visited by spacecraft are derived. Conclusions. The size frequency distribution of the circular depressions is found to have a similar power law distribution to those of 9P/Tempel 1 and 81P/Wild 2. This might imply that they could have been generated by the same process. Orbital integration calculation shows that the surface erosion histories of 81P/Wild 2, and 9P/Tempel 1 could be shorter than those of 67P, 103 P/Hartley 2 and 19P/Borrelly. From this point of view, the circular depressions could be dated back to the pre-JFC phase or the transneptunian phase of these comets. The north-south asymmetry in the distribution of the circular depressions could be associated with the heterogeneous structure of the nucleus of comet 67P and/or the solar insolation history. © ESO, 2016., The support of the national funding agencies of Germany (Deutschen Zentrums fur Luft- und Raumfahrt), France (Centre National d'Etudes Spatales), Italy (Agenzia Spaziale Italiana), Spain (Ministerio de Educacion, Cultura y Deporte), Sweden (Swedish National Space Board; grant No. 74/10:2), and the ESA Technical Directorate is gratefully acknowledged. We are indebted to the whole Rosetta mission team, Science Ground Segment, and Rosetta Mission Operation Control for their hard work making this mission possible. This work was also supported by grant number MOST 104-2119-M-008-024 (TANGOII), NSC 102-2112-M-008-013-MY3, and MOST 104-2111-M-008-020(Space) from the Ministry of Science and Technology of Taiwan, and FDCT grant No. 017/2014/A1 and 039/2013/A2 of Macau Special Administrative Region.
Published: 2016

37. Geologic mapping of the Comet 67P/Churyumov–Gerasimenko's Northern hemisphere

Author: Pedro J. Gutiérrez, F. La Forgia, Nilda Oklay, Frank Scholten, Lorenza Giacomini, M. F. A'Hearn, Dennis Bodewits, Marco Fulle, Olivier Groussin, Antoine Pommerol, Detlef Koschny, Matteo Massironi, Stubbe F. Hviid, J. Knollenberg, M. De Cecco, Francesca Ferri, Nicolas Thomas, J.-R. Kramm, Harald Michalik, V. Da Deppo, Jessica Agarwal, Giampiero Naletto, Michael Küppers, H. U. Keller, Maurizio Pajola, J. J. Lopez Moreno, Francesco Marzari, Frank Preusker, Carsten Güttler, M. A. Barucci, Wing-Huen Ip, Stefano Debei, Jean-Loup Bertaux, Rafael Rodrigo, Laurent Jorda, Ivano Bertini, Björn Davidsson, Cesare Barbieri, Cecilia Tubiana, Mohamed Ramy El-Maarry, Sonia Fornasier, Luca Penasa, Monica Lazzarin, Jean-Baptiste Vincent, Hans Rickman, Luisa Lara, Sara Magrin, Géza Kovács, Gabriele Cremonese, Ekkehard Kührt, Philippe Lamy, Sebastien Besse, Holger Sierks, Stephen C. Lowry, A.-T. Auger, Dipartimento di Geoscienze [Padova], Università degli Studi di Padova = University of Padua (Unipd), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), NASA Ames Research Center (ARC), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Dipartimento di Fisica e Astronomia 'Galileo Galilei', INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), 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, European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), 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), Research and Scientific Support Department, ESTEC (RSSD), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], 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 Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institute of Computer and Network Engineering [Braunschweig] (IDA), European Space Agency, Swedish National Space Board, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Centre National de la Recherche Scientifique (France), Agenzia Spaziale Italiana, Universita degli Studi di Padova, Universität Bern [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), 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), and Consiglio Nazionale delle Ricerche [Roma] (CNR)
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Lineament, 530 Physics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Individual, 67P/ Churyumov-Gerasimenko, Comets, Comets: general, Methods: observational, 01 natural sciences, methods: observational – comets: general – comets: individual: 67P Churyumov Gerasimenko, Astrobiology, Paleontology, Astronomi, astrofysik och kosmologi, Astronomy and Astrophysics, Space and Planetary Science, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, observational [Methods], 010303 astronomy & astrophysics, 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], 520 Astronomy, Northern Hemisphere, general [Comets], Geologic map, 620 Engineering, Methods observational, 13. Climate action, Granulometry, Spatial ecology, individual: 67P/Churyumov-Gerasimenko [comets]
Abstract: The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS), the scientific imaging system onboard the Rosetta mission, has been acquiring images of the nucleus of the comet 67P/Churyumov¿Gerasimenko since 2014 August with a resolution which allows a detailed analysis of its surface. Indeed, data reveal a complex surface morphology which is likely the expression of different processes which occurred at different times on the cometary nucleus. In order to characterize these different morphologies and better understand their distribution, we performed a geologic mapping of comet¿s 67P Northern hemisphere in which features have been distinguished based on their morphological, textural and stratigraphic characteristics. For this purpose, we used narrow-angle camera images acquired in 2014 August and September with a spatial scale ranging from 1.2 to 2.4 m pixel¿1. Several different geologic units have been identified on the basis of their different surface textures, granulometry and morphology. Some of these units are distinctive and localized, whereas others are more common and distributed all over the Northern hemisphere. Moreover, different types of linear features have been distinguished on the basis of their morphology. Some of these lineaments have never been observed before on a comet and can offer important clues on the internal structures of the nucleus itself. The geologic mapping results presented here will allow us to better understand the processes which affected the nucleus¿ surface and thus the origin and evolutionary history of comet 67P/Churyumov¿Gerasimenko. © 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

38. Are fractured cliffs the source of cometary dust jets? Insights from OSIRIS/Rosetta at 67P/Churyumov-Gerasimenko

Author: Frank Scholten, M. De Cecco, Imre Tóth, H. U. Keller, M. F. A'Hearn, M. A. Barucci, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Michael Küppers, R. Rodrigo, Xian Shi, J. L. Bertaux, Stephen C. Lowry, J. B. Vincent, P. L. Lamy, Stefano Mottola, C. Güttler, X. Hu, L. M. Lara, V. Da Deppo, Holger Sierks, Marco Fulle, S. Fornasier, Wing-Huen Ip, Maurizio Pajola, Laurent Jorda, Géza Kovács, Matteo Massironi, Mohamed Ramy El-Maarry, Dennis Bodewits, F. Moreno, G. Cremonese, P. J. Gutierrez, Stubbe F. Hviid, Hans Rickman, Marc Hofmann, Francesco Marzari, Ekkehard Kührt, Giampiero Naletto, Stefano Debei, Cesare Barbieri, Zhong-Yi Lin, Olivier Groussin, Jörg Knollenberg, F. Preusker, P. Gutiérrez-Marquez, J.-R. Kramm, Sebastien Besse, Cecilia Tubiana, J. J. Lopez Moreno, B. J. R. Davidsson, S. Höfner, N. Oklay, Monica Lazzarin, 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), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], 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 Physics and Astronomy [Uppsala], Uppsala University, Gauss Professor 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), 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), DLR Institute of Planetary Research, German Aerospace Center (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), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], 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), European Space Agency, Centre National D'Etudes Spatiales (France), Agenzia Spaziale Italiana, Swedish National Space Agency, Ministerio de Economía y Competitividad (España), German Centre for Air and Space Travel, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], 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), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, 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], High resolution, comets: general / comets: individual: 67P/Churyumov-Gerasimenko, 01 natural sciences, Observational evidence, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Northern Hemisphere, Astronomy, general [Comets], biology.organism_classification, 13. Climate action, Osiris, Geology
Abstract: Context. Dust jets (i.e., fuzzy collimated streams of cometary material arising from the nucleus) have been observed in situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986, and yet their formation mechanism remains unknown. Several solutions have been proposed involving either specific properties of the active areas or the local topography to create and focus the gas and dust flows. While the nucleus morphology seems to be responsible for the larger features, high resolution imagery has shown that broad streams are composed of many smaller jets (a few meters wide) that connect directly to the nucleus surface. Aims. We monitored these jets at high resolution and over several months to understand what the physical processes are that drive their formation and how this affects the surface. Methods. Using many images of the same areas with different viewing angles, we performed a 3-dimensional reconstruction of collimated jets and linked them precisely to their sources on the nucleus. Results. We show here observational evidence that the northern hemisphere jets of comet 67P/Churyumov-Gerasimenko arise from areas with sharp topographic changes and describe the physical processes involved. We propose a model in which active cliffs are the main source of jet-like features and therefore of the regions eroding the fastest on comets. We suggest that this is a common mechanism taking place on all comets., Astronomy and Astrophysics 587 (2016)##EDP Sciences##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.
Published: 2016
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39. The Agilkia boulders/pebbles size-frequency distributions: OSIRIS and ROLIS joint observations of 67P surface

Author: M. F. A'Hearn, Maurizio Pajola, Olivier Groussin, Detlef Koschny, M. A. Barucci, Nicolas Thomas, Björn Davidsson, H.-G. Grothues, Cecilia Tubiana, M. R. El Maarry, Cesare Barbieri, Clement Feller, Holger Sierks, Jessica Agarwal, Frank Scholten, Monica Lazzarin, Carsten Güttler, Wing-Huen Ip, Jean-Baptiste Vincent, Ivano Bertini, Laurent Jorda, Giampiero Naletto, Jakob Deller, Zhong-Yi Lin, Francesco Marzari, R. Rodrigo, J. P. Bibring, Matteo Massironi, Frank Preusker, Stefano Mottola, Stubbe F. Hviid, A. Gicquel, Marco Fulle, Marc Hofmann, Michael Küppers, F. La Forgia, P. J. Gutiérrez, M. De Cecco, Nilda Oklay, Antoine Pommerol, Harald Michalik, Maximilian Hamm, Ralf Jaumann, Steve Boudreault, V. Da Deppo, Harald Michaelis, H. U. Keller, Hans Rickman, Alice Lucchetti, J. L. Bertaux, J. J. Lopez Moreno, Philippe Lamy, Gabriele Arnold, Jörg Knollenberg, Sonia Fornasier, J.-R. Kramm, Stefano Debei, Ekkehard Kührt, L. M. Lara, Gabriele Cremonese, NASA Ames Research Center (ARC), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Department of Information Engineering [Padova] (DEI), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Institute of Geological Sciences [Berlin], Department of Earth Sciences [Berlin], Free University of Berlin (FU)-Free University of Berlin (FU), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), 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), INAF - Osservatorio Astronomico di Padova (OAPD), Department of Industrial Engineering [Padova], Università degli Studi di Trento (UNITN), Physikalisches Institut [Bern], Universität Bern [Bern], 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), Dipartimento di Geoscienze [Padova], Institute of Computer and Network Engineering [Braunschweig] (IDA), Ministerio de Economía y Competitividad (España), Agenzia Spaziale Italiana, Centre National de la Recherche Scientifique (France), Swedish National Space Board, European Space Agency, German Centre for Air and Space Travel, Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), 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: Surface (mathematics), methods: data analysis –methods: statistical – comets: individual: 67P C-G, 010504 meteorology & atmospheric sciences, Infrared, 530 Physics, statistical [methods], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Individual, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Methods statistical, individual: 67P C-G [comets], Astronomi, astrofysik och kosmologi, 0103 physical sciences, Size frequency, data analysis [methods], 67P C-G, Methods, Astronomy, Astrophysics and Cosmology, 14. Life underwater, 010303 astronomy & astrophysics, Joint (geology), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, Statistical-comets, biology, methods: data Analysis methods: statistical comets: individual: 67P C G, 520 Astronomy, Astronomy, Astronomy and Astrophysics, data analysis-methods, biology.organism_classification, 620 Engineering, Space and Planetary Science, Computer Science::Computer Vision and Pattern Recognition, Astrophysics::Earth and Planetary Astrophysics, Osiris
Abstract: By using the images acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) and ROLIS (ROsetta Lander Imaging System) cameras, we derive the size¿ frequency distribution (SFD) of cometary pebbles and boulders covering the size range 0.05¿ 30.0 m on the Agilkia landing site. The global SFD measured on OSIRIS images, reflects the different properties of the multiple morphological units present on Agilkia, combined with selection effects related to lifting, transport and redeposition. Contrarily, the different ROLIS SFD derived on the smooth and rough units may be related to their different regolith thickness present on Agilkia. In the thicker, smoother layer, ROLIS mainly measures the SFD of the airfall population which almost completely obliterates the signature of underlying boulders up to a size of the order of 1 m. This is well matched by the power-law index derived analysing coma particles identified by the grain analyser Grain Impact Analyser and Dust Accumulator. This result confirms the important blanketing dynamism of Agilkia. The steeper SFD observed in rough terrains from 0.4 to 2 m could point out intrinsic differences between northern and southern dust size distributions, or it may suggest that the underlying boulders `peek through¿ the thinner airfall layer in the rough terrain, thereby producing the observed excess in the decimetre size range. Eventually, the OSIRIS SFD performed on the Philae landing unit may be due to water sublimation from a static population of boulders, affecting smaller boulders before the bigger ones, thus shallowing the original SFD., 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

40. Comparative study of water ice exposures on cometary nuclei using multispectral imaging data

Author: Cesare Barbieri, M. A. Barucci, Monica Lazzarin, M. F. A'Hearn, Xian Shi, R. Rodrigo, Olivier Groussin, Jakob Deller, A. Gicquel, J. B. Vincent, Stefano Mottola, Giampiero Naletto, Zhong-Yi Lin, Horst Uwe Keller, Philippe Lamy, Nilda Oklay, Stubbe F. Hviid, Ivano Bertini, Francesco Marzari, Gabriele Cremonese, Björn Davidsson, Detlef Koschny, Holger Sierks, Cecilia Tubiana, I. Hall, Nicolas Thomas, Stefano Debei, P. J. Gutiérrez, Sonia Fornasier, J. M. Sunshine, Ekkehard Kührt, V. Da Deppo, Hans Rickman, L. M. Lara, Marco Fulle, J. J. Lopez Moreno, Maurizio Pajola, Frank Preusker, Géza Kovács, Jörg Knollenberg, Antoine Pommerol, M. De Cecco, Wing-Huen Ip, Laurent Jorda, Marc Hofmann, Michael Küppers, J.-R. Kramm, Dennis Bodewits, Frank Scholten, J. L. Bertaux, Carsten Güttler, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, 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), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), 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], INAF - Osservatorio Astronomico di Trieste (OAT), 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), Institute of Astronomy [Taiwan] (IANCU), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Universität Bern [Bern], European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), German Centre for Air and Space Travel, Centre National de la Recherche Scientifique (France), Agenzia Spaziale Italiana, Ministerio de Economía y Competitividad (España), Swedish National Space Board, European Space Agency, and California Institute of Technology (CALTECH)-NASA
Subjects: 010504 meteorology & atmospheric sciences, 530 Physics, Multispectral image, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, 01 natural sciences, Astrobiology, Astronomi, astrofysik och kosmologi, individual: 67P/Churyumov [Comets], Methods: data analysis, 0103 physical sciences, data analysis [methods], Astronomy, Astrophysics and Cosmology, individual: 103P/Hartley 2 [comets], Techniques: imaging spectroscopy, 010303 astronomy & astrophysics, Comets: individual: 103P/Hartley 2, Comets: individual: 67P/Churyumov, Comets: individual: 9P/Tempel 1, Gerasimenko, 0105 earth and related environmental sciences, Physics, image processing [techniques], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, imaging spectroscopy [techniques], methods: data analysis – techniques: image processing – techniques: imag- ing spectroscopy – comets: individual: 9P/Tempel 1 – comets: individual: 103P/Hartley 2 – comets: individual: 67P/Churyumov–Gerasimenko, 13. Climate action, Space and Planetary Science, individual: 9P/Tempel 1 [comets], Water ice, individual: 67P/Churyumov-Gerasimenko [comets]
Abstract: Deep Impact, EPOXI and Rosetta missions visited comets 9P/Tempel 1, 103P/Hartley 2 and 67P/Churyumov-Gerasimenko, respectively. Each of these three missions was equipped with both multispectral imagers and infrared spectrometers. Bright blue features containing water ice were detected in each of these comet nuclei. We analysed multispectral properties of enriched water ice features observed via Optical, Spectroscopic, and Infrared Remote Imaging System narrow angle camera on comet 67P in the wavelength range of 260¿1000 nm and then compared with multispectral data of water ice deposits observed on comets 9P and 103P. We characterize the UV/VIS properties of water-ice-rich features observed on the nuclei of these three comets. When compared to the average surface of each comet, our analysis shows that the water ice deposits seen on comet 9P are similar to the clustered water-ice-rich features seen on comet 67P, while the water ice deposit seen on comet 103P is more akin to two large isolated water-ice-rich features seen on comet 67P. Our results indicate that the water ice deposit observed on comet 103P contains more water ice than the water-ice-rich features observed on comets 9P and 67P, proportionally to the average surface of each nucleus. © 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society., 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

41. Sublimation of icy aggregates in the coma of comet 67P/Churyumov–Gerasimenko detected with the OSIRIS cameras on board Rosetta

Author: M. De Cecco, Marco Fulle, Wing-Huen Ip, Laurent Jorda, Marc Hofmann, M. F. A'Hearn, Olivier Groussin, Michael Küppers, Stephen C. Lowry, Holger Sierks, S. F. Hviid, Xian Shi, J. L. Bertaux, S. Höfner, F. Scholten, J. B. Vincent, Nafiseh Masoumzadeh, Detlef Koschny, Antoine Pommerol, Giampiero Naletto, Nicolas Thomas, Ivano Bertini, P. J. Gutiérrez, M. A. Barucci, Maurizio Pajola, Nilda Oklay, X. Hu, Cecilia Tubiana, V. Da Deppo, Ekkehard Kührt, Matteo Massironi, Monica Lazzarin, F. Moreno, Cesare Barbieri, Mohamed Ramy El-Maarry, Stefano Mottola, Géza Kovács, Hans Rickman, Francesco Marzari, Jakob Deller, Carsten Güttler, Zhong-Yi Lin, H. U. Keller, R. Rodrigo, A. Gicquel, E. Frattin, Dennis Bodewits, J. J. Lopez Moreno, B. J. R. Davidsson, Philippe Lamy, J.-R. Kramm, Sebastien Besse, Jörg Knollenberg, Imre Toth, Sonia Fornasier, P. Gutiérrez-Marquez, F. Preusker, Jessica Agarwal, Gabriele Cremonese, L. M. Lara, Stefano Debei, German Centre for Air and Space Travel, Agenzia Spaziale Italiana, Swedish National Space Board, European Space Agency, Centre National de la Recherche Scientifique (France), Ministerio de Economía y Competitividad (España), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), 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), 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, 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), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Mechatronics, Optics and Mechanical Engineering Informatics (MOMEI), Budapest University of Technology and Economics [Budapest] (BME), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], ITA, USA, GBR, FRA, DEU, 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: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, 530 Physics, Infrared, Comet, data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Narrow angle, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Methods: numerical, Methods: observational, FOS: Physical sciences, Equinox, Astrophysics, 01 natural sciences, Astronomi, astrofysik och kosmologi, individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, Astronomy, Astrophysics and Cosmology, observational [Methods], comets, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, observational method: numerical method, Physics, Earth and Planetary Astrophysics (astro-ph.EP), methods: data analysis methods: numerical methods: observational comets: individual: 67P/Churyumov–Gerasimenko, numerical [Methods], biology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy, Astronomy and Astrophysics, 620 Engineering, biology.organism_classification, On board, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Sublimation (phase transition), QB651, Osiris, Astrophysics - Earth and Planetary Astrophysics
Abstract: Beginning in 2014 March, the OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) cameras began capturing images of the nucleus and coma (gas and dust) of comet 67P/Churyumov¿Gerasimenko using both the wide angle camera (WAC) and the narrow angle camera (NAC). The many observations taken since July of 2014 have been used to study the morphology, location, and temporal variation of the comet's dust jets. We analysed the dust monitoring observations shortly after the southern vernal equinox on 2015 May 30 and 31 with the WAC at the heliocentric distance Rh = 1.53 AU, where it is possible to observe that the jet rotates with the nucleus. We found that the decline of brightness as a function of the distance of the jet is much steeper than the background coma, which is a first indication of sublimation. We adapted a model of sublimation of icy aggregates and studied the effect as a function of the physical properties of the aggregates (composition and size). The major finding of this paper was that through the sublimation of the aggregates of dirty grains (radius a between 5 and 50 ¿m) we were able to completely reproduce the radial brightness profile of a jet beyond 4 km from the nucleus. To reproduce the data, we needed to inject a number of aggregates between 8.5 × 1013 and 8.5 × 1010 for a = 5 and 50 ¿m, respectively, or an initial mass of H2O ice around 22 kg. © 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

42. The Rosetta campaign to detect an exosphere at Lutetia

Author: H. U. Auster, S. A. Stern, Fred Goesmann, Kathrin Altwegg, Ingo Richter, Harold A. Weaver, Simon Sheridan, Paul D. Feldman, Ian Wright, Marina Galand, Seungwon Lee, M. F. A'Hearn, Andrew Morse, Kurt D. Retherford, Samuel Gulkis, Joel Wm. Parker, Chris Carr, and Dan Andrews
Subjects: Physics, 010504 meteorology & atmospheric sciences, Point source, Comet, Astronomy, Astronomy and Astrophysics, 01 natural sciences, Astrobiology, 13. Climate action, Space and Planetary Science, Asteroid, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Production rate, Exosphere
Abstract: On 10th July 2010 the Rosetta spacecraft passed within 3160 km of asteroid 21 Lutetia during which seven instruments attempted to detect an exosphere. A comparison of the sensitivity is made between the different instruments based on a simple spherical out gassing point source model which was used to infer that the Lutetia exosphere production rate was determined by MIRO to be
Published: 2012

43. Properties of the nuclei and comae of 13 ecliptic comets from Hubble Space Telescope snapshot observations

Author: I. Toth, M. F. A'Hearn, Harold A. Weaver, Laurent Jorda, and Philippe Lamy
Subjects: Effective radius, Physics, Solar System, Space and Planetary Science, Geometric albedo, Hubble space telescope, Comet, Ecliptic, Astronomy, Astronomy and Astrophysics, Astrophysics, Light curve, Reflectivity
Abstract: Context. Knowledge of the size distribution of cometary nuclei and, more generally, of their physical properties is important for constraining models of the formation and evolution of the Solar System. Aims. We report on our on-going effort to determine the ensemble properties of comets based on our success in detecting the nuclei of active comets with the Hubble Space Telescope (HST). Methods. During cycle 8 (July 1999 to June 2000), we observed 13 ecliptic comets with the planetary camera 2 through at least two filters (V and R ) and up to four (B , V , R , I ) for the brightest ones. The ~30 min of HST observational time devoted to each comet did not permit a proper determination of light curves, so our “snapshot” observations yield effective radii, not shapes. Results. Assuming spherical nuclei with a geometric albedo of 0.04 for the R band (except 0.024 for 10P/Tempel 2, as independently measured) and a phase law of 0.04 mag/deg, we obtained the following effective radii: 4P/Faye: 1.77 km, 10P/Tempel 2: 5.98 km, 17P/Holmes: 1.71 km, 37P/Forbes: 0.81 km 44P/Reinmuth 2: 1.61 km, 50P/Arend: 0.95 km, 59P/Kearns–Kwee: 0.79 km, 63P/Wild 1: 1.46 km, 71P/Clark: 0.68 km, 84P/Giclas: 0.90 km, 106P/Schuster: 0.94 km, 112P/Urata–Niijima: 0.90 km, 114P/Wiseman–Skiff: 0.78 km. In our present sample, eight out of thirteen nuclei have sub-kilometer radii. The average color of the observed nuclei is = 0.52± 0.04, which is significantly redder than the Sun. We determined the dust activity parameter of their coma in the R band, and estimated the dust production rates. The average reflectivity gradient of the dust comae of six comets is S ′ [670,792 nm] = 15.2± 2.3% per kA.
Published: 2009

44. Spitzer Space TelescopeObservations of the Nucleus of Comet 103P/Hartley 2

Author: Olivier Groussin, Michael J. S. Belton, Colin Snodgrass, Karen J. Meech, M. F. A'Hearn, William T. Reach, Yanga R. Fernandez, Carey M. Lisse, Tony L. Farnham, and James Bauer
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Effective radius, Physics, Point source, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Active surface, Breakup, Outgassing, medicine.anatomical_structure, Spitzer Space Telescope, Space and Planetary Science, Geometric albedo, medicine, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: We have used the Spitzer 22-um peakup array to observe thermal emission from the nucleus and trail of comet 103P/Hartley 2, the target of NASA's Deep Impact Extended mission. The comet was observed on UT 2008 August 12 and 13, while the comet was 5.5 AU from the Sun. We obtained two 200-frame sets of photometric imaging over a 2.7-hour period. To within the errors of the measurement, we find no detection of any temporal variation between the two images. The comet showed extended emission beyond a point source in the form of a faint trail directed along the comet's anti-velocity vector. After modeling and removing the trail emission, a NEATM model for the nuclear emission with beaming parameter of 0.95 +/- 0.20 indicates a small effective radius for the nucleus of 0.57 +/- 0.08 km and low geometric albedo 0.028 +/- 0.009 (1 sigma). With this nucleus size and a water production rate of 3 x 10^28 molecules s-1 at perihelion (A'Hearn et al. 1995) we estimate that ~100% of the surface area is actively emitting volatile material at perihelion. Reports of emission activity out to ~5 AU (Lowry et al. 2001, Snodgrass et al. 2008) support our finding of a highly active nuclear surface. Compared to Deep Impact's first target, comet 9P/Tempel 1, Hartley 2's nucleus is one-fifth as wide (and about one-hundredth the mass) while producing a similar amount of outgassing at perihelion with about 13 times the active surface fraction. Unlike Tempel 1, it should be highly susceptible to jet driven spin-up torques, and so could be rotating at a much higher frequency. Barring a catastrophic breakup or major fragmentation event, the comet should be able to survive up to another 100 apparitions (~700 yrs) at its current rate of mass loss., Comment: 18 Pages, 3 Figures, 0 Tables Accepted by PASP for publication, 24 June 2009
Published: 2009

45. Asymmetries in the distribution of H2O and CO2 in the inner coma of Comet 9P/Tempel 1 as observed by Deep Impact

Author: Tony L. Farnham, Jessica M. Sunshine, Olivier Groussin, Lori M. Feaga, and M. F. A'Hearn
Subjects: Physics, Solar System, Comet, Ecliptic, Astronomy, Astronomy and Astrophysics, Coma (optics), Spatial distribution, Outgassing, medicine.anatomical_structure, Space and Planetary Science, medicine, Spectroscopy, Nucleus
Abstract: Prior to the impact event, Deep Impact monitored the ambient inner coma of Comet 9P/Tempel 1 at high spatial resolution in July 2005. Gaseous H2O and CO2 are unambiguously detected in the infrared spectra collected with the HRI-IR spectrometer aboard Deep Impact. Detailed distribution maps of these volatiles in the inner coma, within 60 km from the nucleus, are produced from the integrated emission bands of H2O (2.66 μm) and CO2 (4.26 μm). Uncorrelated asymmetries are determined in the spatial distribution of both species indicating chemical heterogeneities within the nucleus. Although present at some abundance surrounding the entire nucleus, H2O has a pronounced enhancement in abundance in the sunward direction rotational phases, evidence that the dominant process of subliming water ice from the nucleus is solar heating. In contrast, CO2 is enhanced in the regions near the negative rotational pole of the nucleus, suggesting localized outgassing there. Both species show an increase in radiance above the limb of the nucleus toward Ecliptic North. The distribution maps also suggest that the process of dust removal from the nucleus is strongly connected to the outgassing of volatiles. Detailed study of these coma asymmetries gives insight to the relative abundances of the dominant molecular components of the inner coma, source regions of the native volatiles, anisotropic outgassing of the nucleus, and the formation and evolution of the nucleus. A quiescent water production rate for Tempel 1 on July 4, 2005, is estimated to be 4.6 × 10 27 molecules s −1 .
Published: 2007

46. Restoration of Images of Comet 9P/Tempel 1 Taken with theDeep ImpactHigh Resolution Instrument

Author: R. L. White, Don J. Lindler, M. F. A’Hearn, and I. Busko
Subjects: Computer science, Comet, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Astronomy and Astrophysics, law.invention, Telescope, Space and Planetary Science, law, Calibration, Noise (video), Deconvolution, Focus (optics), Image restoration, Data compression, Remote sensing
Abstract: In 2005 July, the NASA Deep Impact mission successfully completed a flyby of comet 9P/Tempel 1. A flaw in the prelaunch calibration system resulted in an inability to accurately focus the telescope's High Resolution Instrument, resulting in a significant loss of resolution. However, because of the nature of the blurring process, much of the high-frequency information is retained and can be recovered using deconvolution. We discuss the data-processing requirements and noise modeling needed prior to deconvolution and compare a few popular deconvolution algorithms. All of the algorithms give very similar results. More importantly, we find that none of the algorithms correctly handle the errors resulting from the data compression used on board the spacecraft to compress the 16 bit CCD data to 8 bits prior to transmission of the image to the ground. We present a modification to the Richardson-Lucy deconvolution algorithm that we have successfully used to account for these compression errors.
Published: 2007

47. Dust coma morphology in the Deep Impact images of Comet 9P/Tempel 1

Author: Donald Hampton, Olivier Groussin, Jessica M. Sunshine, Tony L. Farnham, Jian-Yang Li, Carey M. Lisse, Peter H. Schultz, Dennis D. Wellnitz, M. F. A'Hearn, Lucy A. McFadden, C. J. Crockett, and M. J. S. Belton
Subjects: Physics, Solar System, Jet (fluid), Comet, Astronomy, Astronomy and Astrophysics, Coma (optics), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, complex mixtures, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Rotational dynamics, Image resolution
Abstract: We present an overview of the dust coma observations of Comet Tempel 1 that were obtained during the approach and encounter phases of the Deep Impact mission. We use these observations to set constraints on the pre-impact activity of the comet and discuss some preliminary results. The temporal and spatial changes that were observed during approach reveal three distinct jets rotating with a 1.7-day periodicity. The brightest jet produces an arcuate feature that expands outward with a projected velocity of about 12 m s −1 , suggesting that the ambient dust coma is dominated by millimeter-sized dust grains. As the spatial resolution improves, more jets and fans are revealed. We use stereo pairs of high-resolution images to put some crude constraints on the source locations of some of the brightest features. We also present a number of interesting coma features that were observed, including surface jets detected at the limb of the nucleus when the exposed ice patches are passing over the horizon, and features that appear to be jets emanating from unilluminated sources near the negative pole. We also provide a list of 10 outbursts of various sizes that were observed in the near-continuous monitoring during the approach phase.
Published: 2007

48. Automatic removal of cosmic ray signatures in Deep Impact images

Author: Sergei I. Ipatov, Kenneth P. Klaasen, and M. F. A'Hearn
Subjects: Physics, Atmospheric Science, Brightness, Pixel, media_common.quotation_subject, Astrophysics (astro-ph), Comet, FOS: Physical sciences, Aerospace Engineering, Astronomy and Astrophysics, Cosmic ray, Astrophysics, Digital image, Geophysics, Space and Planetary Science, Sky, Comet nucleus, Calibration, General Earth and Planetary Sciences, Remote sensing, media_common
Abstract: The results of recognition of cosmic ray (CR) signatures on a single image were analyzed for several codes written by several authors. For most visual images made during low solar activity at exposure time t>4 s, the number of clusters of bright pixels on an image per second per sq. cm of CCD was about 2-4, both for dark and normal sky images. At high solar activity, it sometimes exceeded 10. The ratio of the number of CR signatures consisting of 'n' pixels obtained at high solar activity to that at low solar activity was greater for greater 'n'. The number of clusters detected as CR signatures on a single infrared image is by at least a factor of several greater than the actual number of CR signatures; the number of clusters based on analysis of two successive dark frames is in agreement with an expected number of CR signatures. Some glitches of false CR signatures include bright pixels presented on different infrared images. Our interactive code allows one to delete long CR signatures and prevents removal of false CR signatures near the edge of a comet., Paper submitted to the journal "Advances in Space Research" (Proceedings of COSPAR-2006)
Published: 2007

49. Searching for the Deep Impact crater on Comet 9P/Tempel 1 using image processing techniques

Author: Don J. Lindler, R. L. White, M. F. A'Hearn, and I. Busko
Subjects: Solar System, Impact crater, Space and Planetary Science, Comet, Astronomy, Image processing, Astronomy and Astrophysics, Ejecta, Image resolution, Image restoration, Geology, Remote sensing, Indirect evidence
Abstract: In this work we attempt to obtain direct images of the crater associated with the impact of the Deep Impact impactor spacecraft on the nucleus of Comet 9P/Tempel 1 on July 4, 2005. The impact generated a large and bright ejecta cloud that hampers the clear view of the post-impact nucleus surface. We used image restoration techniques to enhance spatial resolution and contrast on a subset of selected post-impact high resolution images. No unambiguous evidence for the crater can be found; however, indirect evidence is consistent with a crater size in the 150–200 m range.
Published: 2007

50. Comet 67P/Churyumov-Gerasimenko: Constraints on its origin from OSIRIS observations

Author: H. Rickman, S. Marchi, M. F. A’Hearn, C. Barbieri, M. R. El-Maarry, C. Güttler, W.-H. Ip, H. U. Keller, P. Lamy, F. Marzari, M. Massironi, G. Naletto, M. Pajola, H. Sierks, D. Koschny, R. Rodrigo, M. A. Barucci, J.-L. Bertaux, I. Bertini, G. Cremonese, V. Da Deppo, S. Debei, M. De Cecco, S. Fornasier, M. Fulle, O. Groussin, P. J. Gutiérrez, S. F. Hviid, L. Jorda, J. Knollenberg, J.-R. Kramm, E. Kührt, M. Küppers, L. M. Lara, M. Lazzarin, J. J. Lopez Moreno, H. Michalik, L. Sabau, N. Thomas, J.-B. Vincent, K.-P. Wenzel, 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, Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), 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', Universita degli Studi di Padova, Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, 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], 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 Geoscienze [Padova], Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Department of Industrial Engineering [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), 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), 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 Institute of Planetary Research, German Aerospace Center (DLR), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institut für Datentechnik und Kommunikationsnetze, Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, DEU, ESP, Università degli Studi di Padova = University of Padua (Unipd), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: 67P/Churyumov-Gerasimenko, Solar System, Planetesimal, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Contact binary, Astrophysics, Parent body, medicine, collisional evolution, comets, planetesimals, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Accretion (astrophysics), medicine.anatomical_structure, Comet 67P/Churyumov-Gerasimenko, 13. Climate action, Formation and evolution of the Solar System, Nucleus, Astrophysics - Earth and Planetary Astrophysics
Abstract: One of the main aims of the ESA Rosetta mission is to study the origin of the solar system by exploring comet 67P/Churyumov-Gerasimenko at close range. In this paper we discuss the origin and evolution of comet 67P/Churyumov-Gerasimenko in relation to that of comets in general and in the framework of current solar system formation models. We use data from the OSIRIS scientific cameras as basic constraints. In particular, we discuss the overall bi-lobate shape and the presence of key geological features, such as layers and fractures. We also treat the problem of collisional evolution of comet nuclei by a particle-in-a-box calculation for an estimate of the probability of survival for 67P/Churyumov-Gerasimenko during the early epochs of the solar system. We argue that the two lobes of the 67P/Churyumov-Gerasimenko nucleus are derived from two distinct objects that have formed a contact binary via a gentle merger. The lobes are separate bodies, though sufficiently similar to have formed in the same environment. An estimate of the collisional rate in the primordial, trans-planetary disk shows that most comets of similar size to 67P/Churyumov-Gerasimenko are likely collisional fragments, although survival of primordial planetesimals cannot be excluded. A collisional origin of the contact binary is suggested, and the low bulk density of the aggregate and abundance of volatile species show that a very gentle merger must have occurred. We thus consider two main scenarios: the primordial accretion of planetesimals, and the re-accretion of fragments after an energetic impact onto a larger parent body. We point to the primordial signatures exhibited by 67P/Churyumov-Gerasimenko and other comet nuclei as critical tests of the collisional evolution., Comment: Accepted, to appear on Astronomy & Astrophysics
Published: 2015

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