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201. Characterization of the Abydos region through OSIRIS high-resolution images in support of CIVA measurements

Author: Jean-Pierre Bibring, F. La Forgia, Nilda Oklay, Frank Scholten, Francesco Marzari, J. B. Vincent, Stefano Mottola, Mohamed Ramy El-Maarry, V. Da Deppo, M. De Cecco, Hans Rickman, Cesare Barbieri, Holger Sierks, Matteo Massironi, Alice Lucchetti, Jessica Agarwal, J.-R. Kramm, Stubbe F. Hviid, Marco Fulle, Olivier Groussin, Wing-Huen Ip, Laurent Jorda, Detlef Koschny, P. J. Gutiérrez, J. L. Bertaux, Nicolas Thomas, Stefano Debei, Frank Preusker, Michael Küppers, Maurizio Pajola, François Poulet, Ivano Bertini, R. Rodrigo, Carsten Güttler, H. U. Keller, Sonia Fornasier, Jörg Knollenberg, Michael F. A'Hearn, M. A. Barucci, Björn Davidsson, Cecilia Tubiana, Monica Lazzarin, Giampiero Naletto, J. J. Lopez Moreno, Philippe Lamy, Gabriele Cremonese, Ekkehard Kührt, L. M. Lara, European Space Agency, Ministerio de Educación y Ciencia (España), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), 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), 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), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), 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), 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Universita degli Studi di Padova, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, comets: general, comets: individual: 67P/Churyumov-Gerasimenko, methods: data analysis, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Narrow angle, High resolution, Terrain, 01 natural sciences, comets: general / comets: individual: 67P/Churyumov-Gerasimenko / methods: data analysis, individual: 67P/Churyumov-Gerasimenko [Comets], Methods: data analysis, 0103 physical sciences, Size frequency, comets, data analysis [Methods], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, biology, general [Comets], Astronomy and Astrophysics, biology.organism_classification, Comets: general, 13. Climate action, Space and Planetary Science, Osiris
Abstract: Context. On 12 November 2014, the European mission Rosetta delivered the Philae lander on the nucleus of comet 67P/Churyumov-Gerasimenko (67P). After the first touchdown, the lander bounced three times before finally landing at a site named Abydos. Aims. We provide a morphologically detailed analysis of the Abydos landing site to support Philae's measurements and to give context for the interpretation of the images coming from the Comet Infrared and Visible Analyser (CIVA) camera system onboard the lander. Methods. We used images acquired by the OSIRIS Narrow Angle Camera (NAC) on 6 December 2014 to perform the analysis of the Abydos landing site, which provided the geomorphological map, the gravitational slope map, the size-frequency distribution of the boulders. We also computed the albedo and spectral reddening maps. Results. The morphological analysis of the region could suggest that Philae is located on a primordial terrain. The Abydos site is surrounded by two layered and fractured outcrops and presents a 0.02 km talus deposit rich in boulders. The boulder size frequency distribution gives a cumulative power-law index of -4.0 + 0.3/-0.4, which is correlated with gravitational events triggered by sublimation and/or thermal fracturing causing regressive erosion. The average value of the albedo is 5.8% at λ = 480.7 nm and 7.4% at λ = 649.2 nm, which is similar to the global albedos derived by OSIRIS and CIVA, respectively. © ESO, 2015., The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged
Published: 2016

202. Aswan site on comet 67P/Churyumov-Gerasimenko: Morphology, boulder evolution, and spectrophotometry

Author: Ivano Bertini, Nilda Oklay, Holger Sierks, Pedro J. Gutiérrez, Stefano Debei, Maurizio Pajola, Cesare Barbieri, Francesco Marzari, Matteo Massironi, Stubbe F. Hviid, Harald Michalik, Gabriele Cremonese, Giampiero Naletto, Frank Scholten, Michael Küppers, Zhong-Yi Lin, Marco Fulle, Ekkehard Kürt, Jean-Loup Bertaux, Monica Lazzarin, Sonia Fornasier, Lorenza Giacomini, M. A. Barucci, Fiorangela La Forgia, Detlef Koschny, Nicolas Thomas, Sara Magrin, Jean-Baptiste Vincent, Wing-Huen Ip, Laurent Jorda, Jörg Knollenberg, Stefano Mottola, S. Höfner, Philippe Lamy, Frank Preusker, Rafael Rodrigo, Mariolino De Cecco, J. Rainer Kramm, Jose J. Lopez Moreno, H. U. Keller, Mohamed Ramy El-Maarry, Olivier Groussin, J.-C. Lee, Björn Davidsson, Hans Rickman, Cecilia Tubiana, Michael F. A'Hearn, Luisa Lara, Francesca Ferri, Vania Da Deppo, Jessica Agarwal, Carsten Güttler, 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, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Dipartimento di Geoscienze [Padova], Physikalisches Institut [Bern], Universität Bern [Bern], DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), 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), Department of Information Engineering [Padova] (DEI), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), 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], 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), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, University of Trento [Trento], Department of Mechanical Engineering [Padova], Department of Industrial Engineering [Padova], Universita degli Studi di Padova-Universita degli Studi di Padova, INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Operations Department (ESAC), European Space Astronomy Centre (ESAC), European Space Agency (ESA)-European Space Agency (ESA), Institute of Computer and Network Engineering [Braunschweig] (IDA), 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), NASA-California Institute of Technology (CALTECH), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Universität Bern [Bern] (UNIBE), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Agence Spatiale Européenne = European Space Agency (ESA), Università degli Studi di Padova = University of Padua (Unipd)-Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), European Space Agency, Agenzia Spaziale Italiana, Centre National D'Etudes Spatiales (France), Swedish National Space Agency, Ministerio de Economía y Competitividad (España), and German Centre for Air and Space Travel
Subjects: 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Lineament, Outcrop, 530 Physics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Weathering, Terrain, Astrophysics, shape, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Astronomy and Astrophysics, Space and Planetary Science, Spectrophotometry, 0103 physical sciences, Comets, medicine, Cliff, data analysis [Methods], 010303 astronomy & astrophysics, Southern Hemisphere, Geomorphology, 0105 earth and related environmental sciences, Physics, geography, 67P, geography.geographical_feature_category, medicine.diagnostic_test, cliff, 520 Astronomy, general [Comets], Astronomy, 620 Engineering, collapse
Abstract: [Aims] We provide a detailed morphological analysis of the Aswan site on comet 67P/Churyumov-Gerasimenko (67P). We derive the size-frequency distribution of boulders ≥2 m and correlate this distribution with the gravitational slopes for the first time on a comet. We perform the spectral analysis of this region to understand if possible surface variegation is related to thedifferent surface textures observable on the different units., [Methods] We used two OSIRIS Narrow Angle Camera (NAC) image data sets acquired on September 19 and 22, 2014, with a scale of 0.5 m/px. Gravitational slopes derived from the 3D shape model of 67P were used to identify and interpret the different units of the site. By means of the high-resolution NAC data sets, boulders ≥2.0 m can be unambiguously identified and extracted using the software ArcGIS. Coregistered and photometrically corrected color cubes were used to perform the spectral analyses, and we retrieved the spectral properties of the Aswan units., [Results] The high-resolution morphological map of the Aswan site (0.68 km2) shows that this site is characterized by four different units: fine-particle deposits located on layered terrains, gravitational accumulation deposits, taluses, and the outcropping layered terrain. Multiple lineaments are identified on the Aswan cliff, such as fractures, exposed layered outcrops, niches, and terraces. Close to the terrace margin, several arched features observed in plan view suggest that the margin progressively retreats as a result of erosion. The size-frequency of boulders ≥2 m in the entire study area has a power-law index of −3.9 +0.2/−0.3 (1499 boulders ≥2 m/km2), suggesting that the Aswan site is mainly dominated by gravitational events triggered by sublimation and/or thermal insolation weathering causing regressive erosion. The boulder size-frequency distribution versus gravitational slopes indicates that when higher gravitational slope terrains are considered, only boulders ≤10 m are identified, as well as steeper power-slope indices. In addition, no boulders ≥2 m are observed on slopes ≥50°. This may indicate that larger blocks detached from a sublimating cliff cannot rest at these slopes and consequently fall down. The spectral analysis performed on the site shows that despite different morphologic units, no spectral differences appear in the multiple textures. This may confirm a redistribution of particles across the nucleus as a consequence of airfall, whether coming from Hapi or from the southern hemisphere when it is active during perihelion., The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged.
Published: 2016

203. 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

204. Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere

Author: Michael Küppers, Lorenza Giacomini, Pedro J. Gutiérrez, Francesca Ferri, Michael F. A'Hearn, I. L. Lai, Gabriele Cremonese, Jessica Agarwal, Olivier Groussin, J.-C. Lee, Maurizio Pajola, Luisa Lara, Jörg Knollenberg, Mohamed Ramy El-Maarry, Holger Sierks, Cesare Barbieri, Nilda Oklay, Stefano Debei, Hans Rickman, Rafael Rodrigo, Philippe Lamy, Ekkehard Kührt, Jakob Deller, Wing-Huen Ip, Laurent Jorda, Vania Da Deppo, Zhong-Yi Lin, Jean-Loup Bertaux, Sonia Fornasier, Luca Penasa, Detlef Koschny, M. A. Barucci, Marc Hofmann, Nicolas Thomas, Gábor L. Kovács, J. Rainer Kramm, Xian Shi, Carsten Güttler, Francesco Marzari, Jose J. Lopez Moreno, H. U. Keller, Marco Fulle, Sabrina Ferrari, Ivano Bertini, Monica Lazzarin, Jean-Baptiste Vincent, Björn Davidsson, Matteo Massironi, Cecilia Tubiana, Stubbe F. Hviid, Mariolino De Cecco, Giampiero Naletto, 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), Institute of Space Science [Taiwan], Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Astronomy [Taiwan] (IANCU), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), NASA Ames Research Center (ARC), 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, 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 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), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Universita degli Studi di Padova, Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA), and Consiglio Nazionale delle Ricerche [Roma] (CNR)
Subjects: 010504 meteorology & atmospheric sciences, individual: comet 67P/Churyumov-Gerasimenko [comets], Outcrop, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], observational [methods], Terrain, 01 natural sciences, general [comets], Paleontology, Astronomi, astrofysik och kosmologi, Methods: observational, Comet nucleus, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Southern Hemisphere, 0105 earth and related environmental sciences, Remote sensing, Physics, Comets: general, Comets: individual: comet 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, biology, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Geomorphological mapping, Northern Hemisphere, biology.organism_classification, Osiris
Abstract: International audience; In 2015 May, the Southern hemisphere of comet 67P/Churyumov–Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most extensive geological unit in the Northern hemisphere. In contrast, the Southern hemisphere is dominated by outcropping consolidated terrain. In this work, we provide geomorphological maps of the Southern hemisphere with the distinction of both geological units and linear features. The geomorphological maps described in this study allow us to gain a better understanding of the processes shaping the comet nucleus and the distribution of primary structures such as fractures and strata.
Published: 2016

205. The global shape, density and rotation of Comet 67P/Churyumov-Gerasimenko from preperihelion Rosetta/OSIRIS observations

Author: Ivano Bertini, S.J. Keihm, Olivier Groussin, Robert Gaskell, Michael Küppers, Horst Uwe Keller, Pedro J. Gutiérrez, K.-P. Wenzel, Sonia Fornasier, Detlef Koschny, Jörg Knollenberg, J.-R. Kramm, Giampiero Naletto, Marco Fulle, Nicolas Thomas, Michael F. A'Hearn, Holger Sierks, Luisa Lara, Rafael Rodrigo, Cecilia Tubiana, Carsten Güttler, G. Faury, Stefano Mottola, Monica Lazzarin, Jean-Baptiste Vincent, B. J. R. Davidsson, Jean-Loup Bertaux, Nilda Oklay, Francesco Marzari, Philippe Lamy, M. De Cecco, Stubbe F. Hviid, V. Da Deppo, F. P. Schloerb, Eric Palmer, Wing-Huen Ip, Laurent Jorda, Josef Ďurech, Cesare Barbieri, J. J. Lopez Moreno, Gabriele Cremonese, M. A. Barucci, C. Jackman, Stefano Debei, Simone Marchi, Ekkehard Kührt, Claire Capanna, Hans Rickman, ITA, USA, GBR, FRA, DEU, 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), DLR Institute of Planetary Research, German Aerospace Center (DLR), Astronomical Institute of Charles University, Charles University [Prague] (CU), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), KinetX Aerospace Inc., Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), University of Massachusetts [Amherst] (UMass Amherst), University of Massachusetts System (UMASS), 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, 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), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), 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), 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), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Research and Scientific Support Department, ESTEC (RSSD), DLR, CNES, ASI, MEC, NASA, and SNSB, California Institute of Technology (CALTECH)-NASA, Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), European Space Agency (ESA)-European Space Agency (ESA), and Universität Bern [Bern]
Subjects: Rotation period, Comets, dynamics, 010504 meteorology & atmospheric sciences, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, Image processing, 0103 physical sciences, medicine, Comets, origin, Comets, nucleus, Comets, origin, Data reduction techniques, Space and Planetary Science, Astronomy and Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, nucleus, Astronomy, dynamics, Mass ratio, Bulk density, Astron, medicine.anatomical_structure, Amplitude, 13. Climate action, Nucleus, Principal axis theorem
Abstract: International audience; The Rosetta spacecraft reached Comet 67P/Churyumov-Gerasimenko (hereafter 67P/C-G) in August 2014 at an heliocentric distance of 3.6 a.u. and was then put in orbit around its nucleus to perform detailed observations. Among the collected data are the images acquired by the OSIRIS instrument up to the perihelion passage of the comet in August 2015, which allowed us to map the entire nucleus surface at high-resolution in the visible. Stereophotoclinometry methods have been used to reconstruct a global high-resolution shape model and to monitor its rotational parameters using data collected up to perihelion. The nucleus has a conspicuous bilobate shape with overall dimensions along its principal axes of (4.34 ± 0.02) × (2.60 ± 0.02) × (2.12 ± 0.06) km. The best-fit ellipsoid dimensions of the individual lobes along their principal axes of inertia are found to be 4.10 × 3.52 × 1.63 km and 2.50 × 2.14 × 1.64 km. Their volume amounts to 66% and 27% of the total volume of the nucleus. The two lobes are connected by a “neck” whose volume has been estimated to represent ∼7% of the total volume of the comet. Combining the derived volume of 18.8 ± 0.3 km3 with the mass of 9.982 ± 0.003 × 1012 kg determined by the Rosetta/RSI experiment, we obtained a bulk density of the nucleus of 532±7 kg m-3. Together with the companion value of 535±35 kg m deduced from the stereophotogrammetry shape model of the nucleus (Preusker et al. [2015] Astron. Astrophys. 583, A33), these constitute the first reliable and most accurate determination of the density of a cometary nucleus to date. The calculated porosity is quite large, ranging approximately from 70% to 75% depending upon the assumed density of the dust grains and the dust-to-ice mass ratio. The nature of the porosity, either micro or macro or both, remains unconstrained. The coordinates of the center of gravity are not compatible with a uniform nucleus density. The direction of the offset between the center of gravity and the center of figure suggests that the big lobe has a slightly higher bulk density compared to the small one. the center of mass position cannot be explained by different, but homogenous densities in the two lobes. The initial rotational period of 12.4041 ± 0.0001 h of the nucleus persisted until October 2014. It then slightly increased to a maximum of 12.4304 h reached on 19 May 2015 and finally dropped to 12.305 h just before perihelion on August 10, 2015. A periodogram analysis of the (RA, Dec) direction of the Z-axis of the comet obtained in parallel with the shape reconstruction exhibits a highly significant minima at 11.5 ± 0.5 day clearly indicating an excited rotational state with an amplitude of 0.15 ± 0.03°.
Published: 2016

206. Possible interpretation of the precession of comet 67P/Churyumov-Gerasimenko

Author: Carsten Güttler, F. Scholten, M. A. Barucci, Imre Tóth, Wing-Huen Ip, Laurent Jorda, Claire Capanna, Detlef Koschny, Nicolas Thomas, Ivano Bertini, J. J. López-Moreno, M. De Cecco, F. La Forgia, Stefano Mottola, Jean-Loup Bertaux, Nilda Oklay, Marco Fulle, Cesare Barbieri, Michael Küppers, P. Gutierrez-Marques, Rafael Rodrigo, F. Preusker, Ekkehard Kührt, V. Da Deppo, D. Sabau, Olivier Groussin, Francesco Marzari, L. M. Lara, Jessica Agarwal, Pedro J. Gutiérrez, Sara Magrin, Maurizio Pajola, Michael F. A'Hearn, Holger Sierks, Simone Marchi, J. Knollenberg, Sonia Fornasier, Philippe Lamy, Mohamed Ramy El-Maarry, Hans Rickman, Robert Gaskell, H. U. Keller, Stefano Debei, J.-R. Kramm, Gabriele Cremonese, Björn Davidsson, Cecilia Tubiana, Monica Lazzarin, Giampiero Naletto, Jean-Baptiste Vincent, A. T. Auger, F. Moreno, Stubbe F. Hviid, Antoine Pommerol, L. Maquet, European Space Agency, Swedish National Space Board, Ministerio de Educación, Cultura y Deporte (España), Agenzia Spaziale Italiana, German Centre for Air and Space Travel, Centre National D'Etudes Spatiales (France), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Department of Physics and Astronomy [Uppsala], Uppsala University, DLR Institute of Planetary Research, German Aerospace Center (DLR), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], 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 Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-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 Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), International Space Science Institute [Bern] (ISSI), 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), European Space Research and Technology Centre (ESTEC), 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 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), 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), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Department of Information Engineering [Padova] (DEI), Instituto Nacional de Técnica Aeroespacial (INTA), Center for Space and Habitability (CSH), University of Bern, ITA, USA, GBR, FRA, DEU, 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), European Space Agency (ESA), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], European Space Agency (ESA)-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: Rotation period, 67P/Churyumov-Gerasimenko, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, Angular momentum, 010504 meteorology & atmospheric sciences, 530 Physics, media_common.quotation_subject, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, comets: general / comets: individual: 67P/Churyumov-Gerasimenko, Inertia, 01 natural sciences, individual: 67P/Churyumov-Gerasimenko [Comets], Orientation (geometry), 0103 physical sciences, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, media_common, Physics, 520 Astronomy, general [Comets], 500 Science, Precession, Astrophysics::Earth and Planetary Astrophysics, Right ascension, Principal axis theorem
Abstract: Context. Data derived from the reconstruction of the nucleus shape of comet 67P/Churyumov-Gerasimenko (67P) from images of the OSIRIS camera onboard ROSETTA show evidence that the nucleus rotates in complex mode. First, the orientation of the spin axis is not fixed in an inertial reference frame, which suggests a precessing motion around the angular momentum vector with a periodicity of approximately 257 h ± 12 h.Second, periodograms of the right ascension and declination (RA/Dec) coordinates of the body-frame Z axis show a very significant (higher than 99.99%) periodicity at 276 h ± 12 h, different from the rotational period of 12.40 h as previously determined from light-curve analysis. Aims. The main goal is to interpret the data and associated periodicities of the spin axis orientation in space. Methods. We analyzed the spin axis orientation in space and associated periodicities and compared them with solutions of Euler equations under the assumption that the body rotates in torque-free conditions. Statistical tests comparing the observationally derived spin axis orientation with the outcome from simulations were applied to determine the most likely inertia moments, excitation level, and periods. Results. Under the assumption that the body is solid-rigid and rotates in torque-free conditions, the most likely interpretation is that 67P is spinning around the principal axis with the highest inertia moment with a period of about 13 h. At the same time, the comet precesses around the angular momentum vector with a period of about 6.35 h. While the rotating period of such a body would be about 12.4 h, RA/Dec coordinates of the spin axis would have a periodicity of about 270 h as a result of the combination of the two aforementioned motions. Conclusions. The most direct and simple interpretation of the complex rotation of 67P requires a ratio of inertia moments significantly higher than that of a homogeneous body. © ESO, 2016., 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. P.J.G. and L.M.L. particularly acknowledge funding from projects AyA 2012-32237 and ESP 2014-54062-R.
Published: 2016

207. 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

208. 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

209. The primordial nucleus of comet 67P/Churyumov-Gerasimenko

Author: Stefano Debei, Maria Antonieta Barucci, Holger Sierks, Philippe Lamy, Björn Davidsson, R. Moissl-Fraund, Cecilia Tubiana, Cesare Barbieri, J. J. Lopez Moreno, S. Höfner, Rafael Rodrigo, J.-R. Kramm, Michael F. A'Hearn, Marco Fulle, Colin Snodgrass, Luisa Lara, Michael Küppers, Sonia Fornasier, A.-T. Auger, Francesco Marzari, J. Knollenberg, Gabriele Cremonese, Pedro J. Gutiérrez, Ekkehard Kührt, Monica Lazzarin, Wing-Huen Ip, Laurent Jorda, Maurizio Pajola, Carsten Güttler, Mohamed Ramy El-Maarry, Jean-Baptiste Vincent, H. U. Keller, Hans Rickman, M. De Cecco, Detlef Koschny, Nicolas Thomas, C. Feller, F. La Forgia, Nilda Oklay, V. Da Deppo, Olivier Groussin, Ivano Bertini, Jean-Loup Bertaux, Géza Kovács, Giampiero Naletto, Stefano Mottola, Matteo Massironi, Stubbe F. Hviid, Department of Physics and Astronomy [Uppsala], Uppsala University, 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), 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'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], 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), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Dipartimento di Geoscienze [Padova], 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), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), 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), University of Trento [Trento], Department of Industrial Engineering [Padova], Université Paris Diderot - Paris 7 (UPD7), INAF - Osservatorio Astronomico di Trieste (OAT), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Universität Bern [Bern] (UNIBE), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), ITA, USA, GBR, FRA, DEU, ESP, TWN, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Gauss Professor Akademie der Wissenschaften zu Göttingen, International Space Science Institute [Bern] (ISSI), Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), CNR Istituto di Fotonica e Nanotecnologie [Padova] (IFN), California Institute of Technology (CALTECH)-NASA, 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, comets: individual: 67P/Churyumov-Gerasimenko, Kuiper belt: general, protoplanetary disks, Solar System, 010504 meteorology & atmospheric sciences, Comet dust, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, Astrobiology, 0103 physical sciences, Comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, comets, Kuiper belt, Physics, Comet tail, Nice model, Astronomy, Astronomy and Astrophysics, Accretion (astrophysics), 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Interstellar comet, Physics::Space Physics, comets: individual: 67P/Churyumov-Gerasimenko / Kuiper belt: general / protoplanetary disks, Astrophysics::Earth and Planetary Astrophysics, Formation and evolution of the Solar System
Abstract: We investigate the formation and evolution of comet nuclei and other trans-Neptunian objects (TNOs) in the solar nebula and primordial disk prior to the giant planet orbit instability foreseen by the Nice model. Aims. Our goal is to determine whether most observed comet nuclei are primordial rubble-pile survivors that formed in the solar nebula and young primordial disk or collisional rubble piles formed later in the aftermath of catastrophic disruptions of larger parent bodies. We also propose a concurrent comet and TNO formation scenario that is consistent with observations. Methods. We used observations of comet 67P/Churyumov-Gerasimenko by the ESA Rosetta spacecraft, particularly by the OSIRIS camera system, combined with data from the NASA Stardust sample-return mission to comet 81P/Wild 2 and from meteoritics; we also used existing observations from ground or from spacecraft of irregular satellites of the giant planets, Centaurs, and TNOs. We performed modeling of thermophysics, hydrostatics, orbit evolution, and collision physics. Results. We find that thermal processing due to short-lived radionuclides, combined with collisional processing during accretion in the primordial disk, creates a population of medium-sized bodies that are comparably dense, compacted, strong, heavily depleted in supervolatiles like CO and CO2; they contain little to no amorphous water ice, and have experienced extensive metasomatism and aqueous alteration due to liquid water. Irregular satellites Phoebe and Himalia are potential representatives of this population. Collisional rubble piles inherit these properties from their parents. Contrarily, comet nuclei have low density, high porosity, weak strength, are rich in supervolatiles, may contain amorphous water ice, and do not display convincing evidence of in situ metasomatism or aqueous alteration. We outline a comet formation scenario that starts in the solar nebula and ends in the primordial disk, that reproduces these observed properties, and additionally explains the presence of extensive layering on 67P/Churyumov-Gerasimenko (and on 9P/Tempel 1 observed by Deep Impact), its bi-lobed shape, the extremely slow growth of comet nuclei as evidenced by recent radiometric dating, and the low collision probability that allows primordial nuclei to survive the age of the solar system. Conclusions. We conclude that observed comet nuclei are primordial rubble piles, and not collisional rubble piles. We argue that TNOs formed as a result of streaming instabilities at sizes below ~400 km and that ~350 of these grew slowly in a low-mass primordial disk to the size of Triton, Pluto, and Eris, causing little viscous stirring during growth. We thus propose a dynamically cold primordial disk, which prevented medium-sized TNOs from breaking into collisional rubble piles and allowed the survival of primordial rubble-pile comets. We argue that comets formed by hierarchical agglomeration out of material that remained after TNO formation, and that this slow growth was a necessity to avoid thermal processing by short-lived radionuclides that would lead to loss of supervolatiles, and that allowed comet nuclei to incorporate ~3 Myr old material from the inner solar system.
Published: 2016

210. Sunset jets observed on comet 67P/Churyumov-Gerasimenko sustained by subsurface thermal lag

Author: Cesare Barbieri, J. J. López-Moreno, S. Höfner, Zhong-Yi Lin, M. Hofmann, Stubbe F. Hviid, Francesco Marzari, E. Kührt, M. Küppers, Géza Kovács, Rafael Rodrigo, Holger Sierks, Michael F. A'Hearn, X. Hu, Maurizio Pajola, Jürgen Blum, Monica Lazzarin, Pedro J. Gutiérrez, Sonia Fornasier, Stefano Debei, Xian Shi, Jean-Baptiste Vincent, C. Güttler, Jean-Loup Bertaux, Nilda Oklay, A. Gicquel, Ivano Bertini, J.-R. Kramm, L. M. Lara, Giampiero Naletto, Philippe Lamy, Detlef Koschny, Nicolas Thomas, Marco Fulle, V. Da Deppo, Stefano Mottola, Björn Davidsson, Mohamed Ramy El-Maarry, Hans Rickman, Cecilia Tubiana, Olivier Groussin, M. De Cecco, M. A. Barucci, Gabriele Cremonese, Wing-Huen Ip, Laurent Jorda, Dennis Bodewits, J. Knollenberg, H. U. Keller, 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, Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Physikalisches Institut [Bern], Universität Bern [Bern], DLR Institute of Planetary Research, German Aerospace Center (DLR), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), Institute of Astronomy [Taiwan] (IANCU), 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), 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), 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 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), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Department of Information Engineering [Padova] (DEI), 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), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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: Physics, 67P/Churyumov-Gerasimenko, Comets: individual: 67P/Churyumov-Gerasimenko, Thermal lag, Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, Thermal inertia, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Astrophysics, Sunset, Solar illumination, 01 natural sciences, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], 13. Climate action, 0103 physical sciences, Sublimation (phase transition), Water ice, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: We present observations of sunset jets on comet 67P/Churyumov-Gerasimenko by Rosetta/OSIRIS camera. In late April 2015, when the comet was at a heliocentric distance of ~1.8 AU, clusters of dust jets that originated in the Ma'at region on the comet's small lobe were identified from multipleimages and were apparently sustained for about an hour beyond local sunset. Emanating from the shadowed nucleus, these jets became visible by solar illumination at their apparent sources up to only a few tens of meters above the nucleus surface. We investigate the plausibility of these jets as having been triggered by water ice sublimation and sustained by thermal lag in the subsurface beyond sunset. A general thermo-physical model was parameterized such that the thermal lag in the subsurface is consistent with the elapsed time of observation after sunset. It is found that the sublimation of water ice from a depth of 6 mm and with a low thermal inertia of 50 W m-2 K-1 s1/2 could explain the spatial pattern and evolution of the apparent sources, particularly their disappearance due to the eventual cooling of the subsurface. Our analysis suggests that these sunset jets were essentially day-side dust activities that continued after sunset. Specific observational conditions for the sunset jets constrain their possible sources to mostly within the less abrupt, dusty terrains. The uneven distribution of these jets is possibly related to subsurface inhomogeneities in the dusty area.
Published: 2016

211. Photometry of dust grains of comet 67P and connection with nucleus regions

Author: Frank Scholten, M. A. Barucci, Monica Lazzarin, L. M. Lara, Hans Rickman, Sonia Fornasier, J.-R. Kramm, J. L. Bertaux, Frank Preusker, Holger Sierks, Cecilia Tubiana, Stubbe F. Hviid, Alice Lucchetti, J. B. Vincent, Stefano Mottola, Marco Fulle, Gabriele Cremonese, Jörg Knollenberg, Laurent Jorda, P. J. Gutiérrez, Stefano Debei, Maurizio Pajola, Carsten Güttler, Detlef Koschny, Giampiero Naletto, Nicolas Thomas, Cesare Barbieri, Jessica Agarwal, Michael Kueppers, Ivano Bertini, Roberto Ragazzoni, M. De Cecco, Francesco Marzari, Michael F. A'Hearn, Sara Magrin, B. J. R. Davidsson, Philippe Lamy, J. J. Lopez Moreno, E. Kürt, F. La Forgia, Nilda Oklay, V. Da Deppo, Olivier Groussin, Horst Uwe Keller, W-H. Ip, Emanuele Simioni, R. Rodrigo, ITA, USA, GBR, FRA, DEU, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), 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 Fisica e Astronomia 'Galileo Galilei', Max-Planck-Institut für Sonnensystemforschung (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), 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], 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), 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), European Space Agency (ESA)-European Space Agency (ESA), Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [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), Agence Spatiale Européenne = European Space Agency (ESA), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), 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: Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, 010504 meteorology & atmospheric sciences, photometry, Comet, Coma (optics), comet 67P, Astrophysics, Lambda, 01 natural sciences, Photometry (optics), Phase angle (astronomy), individual: 67P/Churyumov-Gerasimenko [Comets], 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Cosmic dust, Physics, Mineral hydration, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy, general [Comets], Full width at half maximum, 13. Climate action, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], dust grain
Abstract: Aims. Multiple pairs of high-resolution images of the dust coma of comet 67P/Churyumov-Gerasimenko have been collected by OSIRIS onboard Rosetta allowing extraction and analysis of dust grain tracks. Methods. We developed a quasi automatic method to recognize and to extract dust tracks in the Osiris images providing size, FWHM and photometric data. The dust tracks characterized by a low signal-to-noise ratio were checked manually. We performed the photometric analysis of 70 dust grain tracks observed on two different Narrow Angle Camera images in the two filters F24 and F28, centered at λ = 480.7 nm and at λ = 743.7 nm, respectively, deriving the color and the reddening of each one. We then extracted several images of the nucleus observed with the same filters and with the same phase angle to be compared with the dust grain reddening. Results. Most of the dust grain reddening is very similar to the nucleus values, confirming they come from the surface or subsurface layer. The histogram of the dust grain reddening has a secondary peak at negative values and shows some grains with values higher than the nucleus, suggesting a different composition from the surface grains. One hypothesis comes from the negative values point at the presence of hydrated minerals in the comet. © ESO, 2016., The support of the national funding agencies of Germany (DLR), Italy (ASI), France (CNES), Spain (MEC), Sweden (SNSB), and the ESA Technical Directorate is gratefully acknowledged. We thank the ESA teams at ESAC, ESOC, and ESTEC for their work in support of the Rosetta mission.
Published: 2016

212. Comprehensive Transcriptional Analysis of Early-Stage Urothelial Carcinoma

Author: Lars Dyrskjøt, Michael Borre, Karin Mogensen, Torben F. Ørntoft, Roman Nawroth, Gregers G. Hermann, Jørgen Bjerggaard Jensen, Núria Malats, Mattias Höglund, Philippe Lamy, Ewout W. Steyerberg, Sven Wach, Ellen C. Zwarthoff, Tatjana Simic, Kerstin Junker, Jakob Skou Pedersen, Astrid Christine Petersen, Mathilde Borg Houlberg Thomsen, Arndt Hartmann, Ferran Algaba, Karin Birkenkamp-Demtröder, M. Luz Calle, Jakob Hedegaard, Niels Fristrup, Kim E.M. van Kessel, Per-Uno Malmström, Bastian Keck, Cane Tulic, Søren Vang, Iver Nordentoft, Søren Høyer, Willemien Beukers, Francisco X. Real, Robert Stöhr, Tobias Maurer, Anna Katharina Seitz, Benedicte Parm Ulhøi, Marcus Horstmann, Ulrika Segersten, Mirari Marquez, Thomas Reinert, Morten Muhlig Nielsen, Niels Harving, Mattias Aine, Public Health, and Pathology
Subjects: Male, 0301 basic medicine, Medicin och hälsovetenskap, Cancer Research, Cell- och molekylärbiologi, Biology, Bioinformatics, medicine.disease_cause, Medical and Health Sciences, 03 medical and health sciences, 0302 clinical medicine, SDG 3 - Good Health and Well-being, Urologi och njurmedicin, Biomarkers, Tumor, medicine, Cluster Analysis, Humans, Urology and Nephrology, Genetic Predisposition to Disease, APOBEC Deaminases, Gene, Neoplasm Staging, Regulation of gene expression, Cancer och onkologi, Mutation, Bladder cancer, Sequence Analysis, RNA, Gene Expression Profiling, Cancer, Cell cycle, medicine.disease, Survival Analysis, 3. Good health, Chromatin, Gene Expression Regulation, Neoplastic, Gene expression profiling, 030104 developmental biology, Urinary Bladder Neoplasms, Oncology, Cancer and Oncology, 030220 oncology & carcinogenesis, Cancer research, Female, RNA, Long Noncoding, Cell and Molecular Biology
Abstract: Non-muscle-invasive bladder cancer (NMIBC) is a heterogeneous disease with widely different outcomes. We performed a comprehensive transcriptional analysis of 460 early-stage urothelial carcinomas and showed that NMIBC can be subgrouped into three major classes with basal- and luminal-like characteristics and different clinical outcomes. Large differences in biological processes such as the cell cycle, epithelial-mesenchymal transition, and differentiation were observed. Analysis of transcript variants revealed frequent mutations in genes encoding proteins involved in chromatin organization and cytoskeletal functions. Furthermore, mutations in well-known cancer driver genes (e.g., TP53 and ERBB2) were primarily found in high-risk tumors, together with APOBEC-related mutational signatures. The identification of subclasses in NMIBC may offer better prognostication and treatment selection based on subclass assignment.
Published: 2016

213. A high resolution genomic portrait of bladder cancer: correlation between genomic aberrations and the DNA damage response

Author: C-C Pan, V Hvidberg, Niels Fristrup, Philippe Lamy, Troels Schepeler, Laurence Tropia, Torben F. Ørntoft, Lars Dyrskjøt, Thomas Reinert, Thanos D. Halazonetis, Jirina Bartkova, Jiri Bartek, Michael Borre, and Jens R. Laurberg
Subjects: Adult, Cyclin-Dependent Kinase Inhibitor p21, Male, Cancer Research, DNA damage, Cell Cycle Proteins, Biology, Polymorphism, Single Nucleotide, Biomarkers, Tumor, Genetics, medicine, Humans, Genetic Predisposition to Disease, Molecular Biology, Aged, Cell Proliferation, Oligonucleotide Array Sequence Analysis, Sequence Deletion, Aged, 80 and over, Bladder cancer, Homozygote, Resolution (electron density), Intracellular Signaling Peptides and Proteins, Nuclear Proteins, Genomics, Middle Aged, Uniparental Disomy, medicine.disease, DNA-Binding Proteins, Urinary Bladder Neoplasms, Disease Progression, Female, Tumor Suppressor Protein p53, Carrier Proteins, Transcriptome, DNA Damage, Signal Transduction
Abstract: One major challenge in cancer research is to understand the complex interplay between the DNA damage response (DDR), genomic integrity, and tumor development. To address these issues, we analyzed 43 bladder tumor genomes from 22 patients using single nucleotide polymorphism (SNP) arrays, and tissue expression of multiple DDR proteins, including Timeless and its interaction partner Tipin. The SNP profiles confirmed and extended known copy number alterations (CNAs) at high resolution, showed clustering of CNAs at nine common fragile sites, and revealed that most metachronous tumors were clonally related. The occurrence of many novel uniparental disomy regions (UPDs) was of potential functional importance in some tumors because UPDs spanned mutated FGFR3 and PIK3CA alleles, and also homozygous deletion of the CDKN2A tumor suppressor locus. The DDR signaling as evaluated by phospho-epitope-specific antibodies against Ser139-phosphorylated H2A histone family member X (γH2AX), ataxia telangiectasia mutated (ATM), and ATM- and Rad3-related (ATR) was commonly activated in tumors with both moderate and high extent of accumulated genomic aberrations, the latter tumors showing a more frequent loss of ATM expression. Strikingly, the tumor genomes exhibiting the most complex alterations were associated with a high Ki67-proliferation index, abundant Timeless but not Tipin expression, aberrant p53 expression, and homozygous CDKN2A deletions. Of clinical relevance, evaluation of a tissue microarray (TMA; n=319) showed that abundant Timeless expression was associated with risk of progression to muscle-invasive disease (P0.0005; hazard ratio, 2.4; 95% confidence interval, 1.6-3.8) and higher T stage (P0.05). Univariate analysis confirmed this association (P=0.006) in an independent cohort (n=241) but statistical significance was not reached in a multivariate model. Overall, our results are consistent with DDR activation preceding the accumulation of genomic aberrations. Tumors with extensive genomic rearrangements were associated with inactivation of CDKN2A, excessive proliferation, and robust Timeless expression, the latter also correlating with the risk of disease progression. Moreover, we provide evidence to suggest that UPDs likely contribute to bladder tumorigenesis.
Published: 2012

214. Intercomparison of the LASCO-C2, SECCHI-COR1, SECCHI-COR2, and Mk4 Coronagraphs

Author: Philippe Lamy, Angelos Vourlidas, Russell J. Hewett, William T. Thompson, A. Llebaria, Richard A. Frazin, A. M. Vásquez, Joan Burkepile, 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: Brightness, business.product_category, 010504 meteorology & atmospheric sciences, Ciencias Físicas, 01 natural sciences, 7. Clean energy, law.invention, law, 0103 physical sciences, 010303 astronomy & astrophysics, Coronagraph, 0105 earth and related environmental sciences, Remote sensing, Eclipse, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Spacecraft, business.industry, Stray light, Astronomy, Astronomy and Astrophysics, CORONAGRAPH, SOLAR CORONA, Astronomía, Trustworthiness, Rocket, 13. Climate action, Space and Planetary Science, ELECTRON DENSITY, business, Longitude, CIENCIAS NATURALES Y EXACTAS
Abstract: In order to assess the reliability and consistency of white-light coronagraph measurements, we report on quantitative comparisons between polarized brightness [pB] and total brightness [B] images taken by the following white-light coronagraphs: LASCO-C2 on SOHO, SECCHI-COR1 and -COR2 on STEREO, and the ground-based MLSO-Mk4. The data for this comparison were taken on 16 April 2007, when both STEREO spacecraft were within 3. 1 {ring operator} of Earth's heliographic longitude, affording essentially the same view of the Sun for all of the instruments. Due to the difficulties of estimating stray-light backgrounds in COR1 and COR2, only Mk4 and C2 produce reliable coronal-hole values (but not at overlapping heights), and these cannot be validated without rocket flights or ground-based eclipse measurements. Generally, the agreement between all of the instruments' pB values is within the uncertainties in bright streamer structures, implying that measurements of bright CMEs also should be trustworthy. Dominant sources of uncertainty and stray light are discussed, as is the design of future coronagraphs from the perspective of the experiences with these instruments. © 2012 Springer Science+Business Media B.V. Fil: Frazin, Richard A.. University Of Michigan, Ann Arbor; Estados Unidos Fil: Vasquez, Alberto Marcos. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina Fil: Thompson, William T.. Nasa Goddard Space Flight Center; Estados Unidos Fil: Hewett, Russell J.. University of Illinois. Urbana - Champaign; Estados Unidos. Massachusetts Institute of Technology; Estados Unidos Fil: Lamy, Philippe. Laboratoire D'astrophysique de Marseille; Francia Fil: Llebaria, Antoine. Laboratoire D'astrophysique de Marseille; Francia Fil: Vourlidas, Angelos. Spece Sciences División. Naval Research Laboratory; Estados Unidos Fil: Burkepile, Joan. The Earth And Sun Systems Laboratory; Estados Unidos
Published: 2012

215. Characterization of OSIRIS NAC filters for the interpretation of multispectral data of comet 67P/Churyumov-Gerasimenko

Author: Carsten Güttler, Cesare Barbieri, Marco Fulle, J. J. López-Moreno, Sebastien Besse, Jörg Knollenberg, Cecilia Tubiana, Jessica Agarwal, M. De Cecco, J. L. Bertaux, Michael F. A'Hearn, Holger Sierks, Sonia Fornasier, F. La Forgia, Giampiero Naletto, Francesco Marzari, Nilda Oklay, Detlef Koschny, Ivano Bertini, Monica Lazzarin, Nicolas Thomas, Wing-Huen Ip, Laurent Jorda, Harald Michalik, V. Da Deppo, Antonella Barucci, J.-R. Kramm, R. Rodrigo, Hans Rickman, Maurizio Pajola, B. J. R. Davidsson, Philippe Lamy, Michael Küppers, Stefano Debei, P. J. Gutiérrez, Gabriele Cremonese, Ekkehard Kührt, L. M. Lara, Stubbe F. Hviid, Olivier Groussin, Horst Uwe Keller, J. B. Vincent, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), 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), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), 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 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), 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], National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, DEU, ESP, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), 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: 67P/Churyumov-Gerasimenko, 530 Physics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Spectral line, Optics, Methods: data analysis, Rosetta, Techniques: imaging spectroscopy, Remote sensing, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, Multispectral data, biology, business.industry, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 520 Astronomy, Cometary Science, Astronomy and Astrophysics, biology.organism_classification, Reflectivity, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Space and Planetary Science, Wavelength, Astrophysics::Earth and Planetary Astrophysics, Osiris, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Context. We interpret multicolor data from OSIRISNAC for the remote-sensing exploration of comet 67P/Churyumov-Gerasimenko. Aims: We determine the most meaningful definition of color maps for the characterization of surface variegation with filters available on OSIRIS NAC. Methods: We analyzed laboratory spectra of selected minerals and olivine-pyroxene mixtures seen through OSIRIS NAC filters, with spectral methods existing in the literature: reflectance ratios, minimum band wavelength, spectral slopes, band tilt, band curvature, and visible tilt. 2O3 filters let us define regions that may significantly differ in composition. Appendices are available in electronic form at "http://www.aanda.org/10.1051/0004-6361/201525994/olm"
Published: 2015

216. A Novel Technique for Measuring the Solar Radius from Eclipse Light Curves - Results for 2010, 2012, 2013, and 2015

Author: Olivier Floyd, G. Faury, Patrick Rocher, Jean-Yves Prado, S. Koutchmy, Philippe Lamy, 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), AKKA Technologies, 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 Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: Physics, Kaguya, 010504 meteorology & atmospheric sciences, Astronomy, Astronomy and Astrophysics, Solar radius, Photometer, Radius, Light curve, Ephemeris, 01 natural sciences, law.invention, Wavelength, 13. Climate action, Space and Planetary Science, law, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Eclipse
Abstract: We report on a novel technique for measuring the solar radius during total solar eclipses that exploits light curves recorded just before and after second and third contacts. The measurements are performed by pre-programmed photometers that are deployed over the eclipse paths and are operated without supervision. The recorded light curves are compared to synthetic light curves calculated from high-accuracy ephemerides and lunar-limb profiles constructed from the topographic model of the Moon provided by the Kaguya lunar space mission. A minimization process between the two sets of curves yields the solar radius. Altogether, seventeen determinations have been obtained during the past four total eclipses with the following averages (at a wavelength of 540 nm and scaled to 1 AU): $959.94\pm0.02~\mbox{arcsec}$ on 11 July 2010, $960.02\pm0.04~\mbox{arcsec}$ on 13 November 2012, $959.99\pm0.09~\mbox{arcsec}$ on 3 November 2013, and $960.01\pm0.09~\mbox{arcsec}$ on 20 March 2015. Part of the differences between these four values may be attributed to weather conditions. Averaging the whole set of measurements yields a radius of $959.99\pm0.06~\mbox{arcsec}$ ( $696{,}246\pm45~\mbox{km}$ ), which agrees excellently well with the most recent data and supports an upward revision of the standard IAU value, as previously suggested.
Published: 2015

217. Attenuation of the beta-catenin/TCF4 complex in colorectal cancer cells induces several growth-suppressive microRNAs that target cancer promoting genes

Author: Kasper Thorsen, Claus L. Andersen, Daniel C. Liebler, Kristian Helin, Torben F. Ørntoft, Iver Nordentoft, Philippe Lamy, Anja Holm, Lise Lotte Christensen, Troels Schepeler, Eva M. Riising, and Patrick J. Halvey
Subjects: Male, Cancer Research, Beta-catenin, Microarray, Colon, MiRNA binding, Transcriptome, Transcription Factor 4, Cell Line, Tumor, microRNA, Tumor Cells, Cultured, Genetics, Humans, RNA, Messenger, RNA, Small Interfering, Luciferases, Wnt Signaling Pathway, Molecular Biology, Transcription factor, beta Catenin, Aged, Cell Proliferation, Genes, Dominant, Oligonucleotide Array Sequence Analysis, Aged, 80 and over, biology, Basic Helix-Loop-Helix Leucine Zipper Transcription Factors, Reverse Transcriptase Polymerase Chain Reaction, Gene Expression Profiling, Rectum, Wnt signaling pathway, Oncogenes, Middle Aged, Gene expression profiling, MicroRNAs, Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization, biology.protein, Cancer research, Female, Colorectal Neoplasms, Chromatography, Liquid, Transcription Factors
Abstract: Aberrant activation of the Wnt signaling pathway is causally involved in the formation of most colorectal cancers (CRCs). Although detailed knowledge exists regarding Wnt-regulated protein-coding genes, much less is known about the possible involvement of non-coding RNAs. Here we used TaqMan Array MicroRNA Cards, capable of detecting 664 unique human microRNAs (miRNAs), to describe changes of the miRNA transcriptome following disruption of beta-catenin/TCF4 activity in DLD1 CRC cells. Most miRNAs appeared to respond independent of host gene regulation and proximal TCF4 chromatin occupancy as inferred from expression microarray and ChIP–chip data. A module of miRNAs induced by abrogated Wnt signaling in vitro was downregulated in two independent series of human primary CRCs (n=76) relative to normal adjacent mucosa (n=34). Several of these miRNAs (miR-145, miR-126, miR-30e-3p and miR-139-5p) markedly inhibited CRC cell growth in vitro when ectopically expressed. By using an integrative approach of proteomics and expression microarrays, we found numerous mRNAs and proteins to be affected by ectopic miR-30e-3p levels. This included HELZ and PIK3C2A that were directly repressed by several miRNA binding sites as confirmed by luciferase reporter assays in combination with mutational analyses. Finally, small interfering RNA-mediated downregulation of PIK3C2A, but not HELZ, was sufficient on its own to restrict CRC cell growth. Collectively, our study demonstrates that multiple miRNAs are upregulated as a consequence of forced attenuation of Wnt signaling in CRC cells, and some of these miRNAs inhibit cell growth with concomitant suppression of several growth-stimulatory cancer-related genes. Aberrant activation of the Wnt signaling pathway is causally involved in the formation of most colorectal cancers (CRCs). Although detailed knowledge exists regarding Wnt-regulated protein-coding genes, much less is known about the possible involvement of non-coding RNAs. Here we used TaqMan Array MicroRNA Cards, capable of detecting 664 unique human microRNAs (miRNAs), to describe changes of the miRNA transcriptome following disruption of beta-catenin/TCF4 activity in DLD1 CRC cells. Most miRNAs appeared to respond independent of host gene regulation and proximal TCF4 chromatin occupancy as inferred from expression microarray and ChIP-chip data. A module of miRNAs induced by abrogated Wnt signaling in vitro was downregulated in two independent series of human primary CRCs (n=76) relative to normal adjacent mucosa (n=34). Several of these miRNAs (miR-145, miR-126, miR-30e-3p and miR-139-5p) markedly inhibited CRC cell growth in vitro when ectopically expressed. By using an integrative approach of proteomics and expression microarrays, we found numerous mRNAs and proteins to be affected by ectopic miR-30e-3p levels. This included HELZ and PIK3C2A that were directly repressed by several miRNA binding sites as confirmed by luciferase reporter assays in combination with mutational analyses. Finally, small interfering RNA-mediated downregulation of PIK3C2A, but not HELZ, was sufficient on its own to restrict CRC cell growth. Collectively, our study demonstrates that multiple miRNAs are upregulated as a consequence of forced attenuation of Wnt signaling in CRC cells, and some of these miRNAs inhibit cell growth with concomitant suppression of several growth-stimulatory cancer-related genes.Oncogene advance online publication, 3 October 2011; doi:10.1038/onc.2011.453.
Published: 2011

218. Properties of the nuclei and comae of 10 ecliptic comets from Hubble Space Telescope multi-orbit observations★

Author: Harold A. Weaver, Laurent Jorda, Philippe Lamy, Michael F. A'Hearn, and I. Toth
Subjects: Physics, Effective radius, Solar System, 010504 meteorology & atmospheric sciences, Comet, Ecliptic, Astronomy, Astronomy and Astrophysics, Astrophysics, Light curve, 01 natural sciences, Color index, 13. Climate action, Space and Planetary Science, Geometric albedo, Hubble space telescope, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
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 (V − R) = 0.52 ± 0.04, which is significantly redder than the Sun. We determined the dust activity parameter Afρ 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: 2011

219. Radiation forces on small particles in the Solar System: A re-consideration

Author: Joseph A. Burns, Steven Soter, and Philippe Lamy
Subjects: Physics, ICARUS, Solar System, Space and Planetary Science, Astronomy and Astrophysics, Astrophysics, Small particles, Limiting, Radiation, Interplanetary spaceflight, Celestial mechanics, Mathematical physics
Abstract: We respond to Klacka et al. (Klacka, J., Petržala, J., Pastor, P., Komar, L. [2014]. Icarus, this issue, http://dx.doi.org/10.1016/j.icarus.2012.06.044 .), who have criticized many previous derivations of the acceleration experienced by a spherical interplanetary particle owing to the Sun’s radiation. Much of their criticism arises from differences in semantics and notation as well as effects that are unimportant at Solar System speeds. Accordingly, in the appropriate limiting cases, most published expressions for the radiation forces, such as that found in Burns et al. (Burns, J.A., Lamy, P.L., Soter, S. [1979]. Icarus 40 1–48), are correct and duplicate the results of Klacka et al. (Klacka, J., Petržala, J., Pastor, P., Komar, L. [2014]. Icarus, this issue, http://dx.doi.org/10.1016/j.icarus.2012.06.044 ).
Published: 2014

220. Abstract 3653: Sequencing of plasma cfDNA from patients with locally advanced bladder cancer for surveillance and therapeutic efficacy monitoring

Author: Karin Birkenkamp-Demtröder, Himanshu Sethi, Lars Dyrskjøt, Samantha Navarro, Cheng-Ho Jimmy Lin, Ann Taber, Hsin-Ta Wu, Emil Christensen, Iver Nordentoft, Ryan Swenerton, Mads Agerbæk, Ramya Srinivasan, John So, Tony Tin, Shruti Sharma, Philippe Lamy, Svetlana Shchegrova, Jørgen Bjerggaard Jensen, Bernhard Zimmermann, Spenser Alexander, and Solomon Moshkevich
Subjects: Oncology, Cancer Research, medicine.medical_specialty, Bladder cancer, business.industry, Internal medicine, medicine, Locally advanced, business, medicine.disease, Plasma.cfDNA
Abstract: Minimally invasive methods for assessment of tumor burden, early detection of disease relapse and for monitoring therapeutic efficacy are needed to improve individualized follow-up and treatment for patients diagnosed with bladder cancer. The ability to predict pathologic complete response after neoadjuvant chemotherapy (NAC) through detection of ctDNA in plasma may enable strategies for bladder preservation. The aim of the study was to use patient-specific mutations to identify residual disease, metastatic relapse and to monitor treatment response in longitudinally collected plasma samples. For this, 50 patients diagnosed with locally advanced muscle-invasive bladder cancer (MIBC) and scheduled for chemotherapy were prospectively recruited between 2013 and 2017. In total, 42 patients received four cycles of cisplatin-based NAC prior to cystectomy and 82% showed response (pathologic downstaging). Eight patients received 2-6 cycles of cisplatin-based first-line chemotherapy due to diagnosis of T4b or lymph node metastasis prior to cystectomy (3CR, 2PR, 2PD, 1 ongoing). So far, 8/50 patients (16%) experienced disease relapse and three patients had metastatic progression. The mean follow-up time after radical cystectomy (RC) was 320 days (65-973); the mean follow-up time for disease-free patients was 397 days (119-778). Whole-exome sequencing (106x mean target coverage) of tumor and germline DNA was performed from a time point before systemic treatment. MUTECT2 identified a mean of 33 high (6-121), 340 (67-2838) moderate and 223 (29-2955) low-impact SNVs or insertion-deletions (InDels) per tumor. High-impact mutations in known cancer genes such as TP53 (60%), KDM6A (34%), ARID1A (32%), RB1 (28%), BRCA2 (26%), FGFR3 (22%) and ERCC2 (20%) were identified with no significant difference between responders vs nonresponders. Signatures 2, 13 (APOBEC), and 3 (BRCA) were frequently identified, with signature 13 being more prevalent in nonresponders (p=0.05). Personalized, multiplex-PCR assay-panels were individually designed, targeting each patient's tumor-specific mutations in plasma. Targeted sequencing was performed using cfDNA from 4-16 longitudinally collected plasma from each patient taken pre- and post-systemic therapy and at scheduled control visits after RC. In a blinded fashion, ctDNA was analyzed and results were compared to pathologic response and radiographic imaging data for each patient. Conclusion: Preliminary results indicated that analysis of plasma cfDNA is an appropriate method to detect metastatic relapse after RC and to monitor treatment efficacy. Here we perform a larger ctDNA study, applying direct sequencing of plasma cfDNA using highly sensitive NGS methods to determine clinical applicability of the method. Data collection is ongoing and all details will be presented at the AACR 2018 meeting. Citation Format: Karin Birkenkamp-Demtröder, Emil Christensen, Shruti Sharma, Ann Taber, Mads Agerbæk, Himanshu Sethi, Hsin-Ta Wu, Svetlana Shchegrova, Philippe Lamy, Iver Nordentoft, Ryan Swenerton, Samantha Navarro, Tony Tin, Ramya Srinivasan, John So, Spenser Alexander, Solomon Moshkevich, Bernhard Zimmermann, Cheng-Ho Jimmy Lin, Jørgen Bjerggaard Jensen, Lars Dyrskjøt. Sequencing of plasma cfDNA from patients with locally advanced bladder cancer for surveillance and therapeutic efficacy monitoring [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3653.
Published: 2018

221. High Risk of Anal and Rectal Cancer in Patients With Anal and/or Perianal Crohn’s Disease

Author: Laurent Beaugerie, Fabrice Carrat, Stéphane Nahon, Jean-David Zeitoun, Jean-Marc Sabaté, Laurent Peyrin-Biroulet, Jean-Frédéric Colombel, Matthieu Allez, Jean-François Fléjou, Julien Kirchgesner, Magali Svrcek, Jacques Cosnes, Jean-Pierre Gendre, Marc Lémann, Xavier Hébuterne, Antoine Cortot, Yoram Bouhnik, David Laharie, Jean Louis Dupas, Bernard Flourié, Eric Lerebours, Bernard Messing, Guillaume Cadiot, Philippe Marteau, Jean-Claude Soulé, Jean-Marc Gornet, Michel Veyrac, Bernard Duclos, Philippe Beau, Arnaud Bourreille, Philippe Baumer, Franck Carbonnel, Denis Heresbach, Etienne-Henry Metman, Christian Florent, Antoine Blain, Jean-Luc Faucheron, Bruno Bonaz, Xavier Roblin, Pascal Potier, Christian Boehm, Thierry Kurtz, Hervé Lamouliatte, Isabelle Nion-Larmurier, Jean-Charles Delchier, Stanislas Chaussade, Anne Marie Weiss, Jean Pierre Cézard, Laurent Siproudhis, Daniel Sondag, Raymond Jian, Jean-Christophe Souquet, Pierre Bord, Benoit Coffin, Hélène D’almagne, Patrick Delasalle, Régis Fournier, Maryan Cavicchi, Marc-Henry Souffran, Luc Vandromme, Claire Guedon, Philippe Seksik, Christophe Michiels, Pascal Renard, Patrice Rogier, Sylvie Gouilloud, André Rotenberg, Guillaume Savoye, Alain Thevenin, Laurent Mallet, Franck Brazier, Francois Jean, Anne-Marie Justum, Jean-Paul Latrive, Jean-Luc Gerbal, Robert Pierrugues, Gérard Chardonnal, Laurence Picon, Nicole Reix, Nicolas Drouët D’aubigny, Hervé Uettwiller, Anne Courillon Mallet, Alain Palacci, Raoul-Jacques Bensaude, Pierre Bonniaud, Olivier Empinet, Andrée Nisard, Alain Rudelli, Bernard Tubiana, Philippe Capelle, Alain Dabadie, Daniel Evard, Pierre-Emile Julien, Magali Picon-Coste, Stéphane Schneider, Denis Goldfain, Jérôme Bellanger, Jean-Pierre Blondelot, Philippe Lamy, Sébastien Lemière, Jean Francois Mockly, Benoit Pellat, Gilles Gatineau-Sailliant, Bernard Nalet, Stéphane Nancey, Daniel Kusielewicz, Patrick Loison, Jean-Michel Popot, François Merite, Jean-Pol Roux, Pauline Afchain, Alain Blanquart, Laurent Heyries, Marc Reville, Dominique Viron, Frank Zerbib, Christophe Claviere, Didier Léostic, Philippe Pouderoux, Alain Moitry, Hervé Hagège, Jean-Pierre Hugot, Benoit Humeau, Jean-Marc Sabate, Emmanuel Lederman, Dominique Lescut, Fabrice Luneau, Bruno Mesnard, Lionel Smadja, Michel Steinberg, Marc Brun, Gilles Macaigne, Jean Luc Marchal, Stéphane Ollivier, Dominique Ouvry, Jean Paul Perche, Serge Rambaud, Robert Benamouzig, Jean Louis Cazenave, Jean-Charles Coffin, Martine Blazquez, Marion Lagneau, Bruno Person, Christian Wittersheim, Bertrand Napoleon, Israël Cemachovic, Franck Iglicki, Mehran Howaizi, Eric Leprince, Bruno Leurent, Thierry Morin, Riad Darsouni, Alain Attar, Philippe Baron, Anne Breton, Jean Marie Gillion, Jean-Marc Guemene, Claude Jouffre, Xavier Moreau, Pierre Claude, André Quinton, Vered Abitbol, Jean Michel Brichard, Benoit Desaint, Martin Bouygues, Philippe Chatrenet, Marcelo Salmeron, Jean Silvie, Bruno Waldner, Yves Emery, Armand Moraillon, Daniel Kunkel, Philippe Dubois, Patrick Faure, Christian L'Hirondel, Jean-Eric Labérenne, Pierre Moreau, Adelino Pereira, Genevieve Plihon, Thierry Wolff, Yann Ngo, Arnaud Boruchowicz, Béatrice Jost, Jean Pierre Gotlib, Odile Danne, Philippe Raoux, Marie-José Ramond-Bouhali, Andre Baetz, Bruno Veyres, Christian Chapoutot, Gérard Le Dréau, Jérôme Filippi, Jean Mudry, Philippe Kalt, Sophie Minault, Pierre-André Bounin, Tony Andréani, Jacky Charneau, Didier Reijasse, Jean-Louis Bolze, Jean Luc Thaunat, Christian Le Couteulx, Chantal Maurage, Robert Bader, Philippe Codjovi, Jean-Luc Migairou, Alain Morali, Philippe Rey, Bruno Richard Molard, Richard Petit, Stéphane Koch, Philippe Cassan, Jean-Paul Deschamps, Christine Meicler Caby, Jean-Jacques Meurisse, Philippe Prades, James Boulant, Michel Diacono, Jean-Marie Monsch, J-François Dupuy, Guy Bellaiche, Martine Guegan, Jean-Marc Comte, Jean-Michel Cayla, Francois Le Tallec, Franck Meurisse, Philippe Desurmont, Laurent Roget, Philippe Bouyssou, Bruno Le Gall, Francis Bloch, Loic Larvol, Monique Jullien, Jacques Moreau, Laurent Rebouissoux, Bruno Decroix, Nina Dib, Paul Dieterling, Frédéric Lenormand, Emmanuel Lagier, Philippe Fallourd, Serge Charpin, Hugues Bertrand, Gilles Bommelaer, Daniel Battistelli, Bernard Delon, Lionel Dentant, Etienne Dorval, Jérôme Dumortier, Eric Gaye-Bareyt, Yves Gerosa, Chantal Guez, Martine Mornet, Paul Benfredj, René Piperaud, Noel Stremsdoerfer, Eric Verdier, Alain Grinholtz, Georges Barjonet, Antoine See, Ramuntxo Arotçarena, Anne Baudet, Joel Broyer, Antoine Charachon, Hugues Blondon, Pascal Mouton, Hubert Claudez, Jacques Labat-Labourdette, Jacques Haëm, Patrick Estable, Patrick Levy, Alain Rosenbaum, Yvon Balavoine, Alain Blanchi, Pierre Coutarel, Nadege Delaperriere, Michel Dervichian, Francis Marois, Jacques Seroka, Laurent Michaud, Olivier Leroy, Emmanuel Meyran, Bernard Poilroux, Abdallah Tensaouti, Thierry Paupard, Dominique Agard, Sandrine Beaulieu, Kader Benfiguig, Patrice Capony, Jean Cottereau, Pierre Desreumaux, Jean-Michel Dramard, Mathieu Duché, Patrick Mamou, Isabelle Etienney, Gilles D'Abrigeon, Béatrice Godeberge, Gilbert Tucat, Jean Puech, Jean Roger, Marie-George Lapalus, Paul Bauret, Philippe Houcke, Béatrice Pornin, Bruno Champigneulle, Laurent Cuissard, Xavier-Richard David, Frédéric Lombard, Antoine Granveau, Jean-François Hamon, Olivier Ink, Fabienne Blondel, Alain Namias, Didier Pillon, Antoine Reignier, Gilles Tordjman, Christos Christidis, Simon Zirabe, Michel Audebert, Eric Bion, Claude Bourgeaux, Cécile Poupardin, Philippe Deplaix, Gérard Fratini, Thierry Garnier, Gerard Desseaux, Hervé Magois, Sylvain Lochum, Jean-Francois Vergier, Patrick Texereau, Christel Rat, Francoise Uzzan, Alain Vidal, Nadia Vinante, Bernard Watrin, Cécile Wurtz-Huckert, Bruno Barre, Dominique Chaslin Ferbus, Jean-François Contou, Dominique Coupier, Benoit David, Dany Gargot, Denis Huc, Remy Barraya, Roger Faroux, Jean-Luc Fourgeaud, Hubert Grimprel, Jean Auroux, Jean-François Rey, Jean Pierre Arnoux, Franck Lentini, Ludovic Tardy, Olivier Mouterde, Claire Spyckerelle, Bruno Vacherot, Alain Weissman, Michel Alpérine, Anne Le Sidaner, Pierre-Olivier Bonnet-Eymard, Jean Louis Colson, Daniel Pellet, Bernard Deltombe, André Edouard, Henri Maechel, Jean-Claude Jaillet, Julien Genes, Anne-Marie Leveque, Damien Lucidarme, Philippe Maignan, Nathalie Mallier Gehrke, Jérôme Sanchez, Frank Tusseau, Alban Casteur, Jacques Bottlaender, Denis Constantini, Thierry Coton, Philippe Even, Francois Druart, François Riot, Jean-Michel Gauchet, Geneviève Hecquet, Gerard Henry, Patrick Hochain, Jean Pierre Arpurt, Abdelkrim Medini, Michele Dartois-Hoguin, Henri Moindrot, Philippe Emery, Pierre Periac, Annie Prunier, Pascal Renkes, Christine Tawil-Longreen, Edmond Vincent, René-Louis Vitte, Christian Loeb, Alain Carwana, Didier Barbereau, Philippe Bohon, Céline Corrieri-Baizeau, Daniel Sahy, Philippe Derreveaux, Dominique David, François Desbazeille, Patrick Fontenelle, Jean Luc Slama, Yvon Le Mercier, Michel Certin, Jean Jacques Reig, Isabelle Rosa, Thierry Helbert, Patrick Tounian, Luc Turner, Valéry Perot, Luc Aillet, Arnaud Pauwels, Philippe Barré, Bernard Nury, Claude Cazalbou, Franck Devulder, Alain Durget, Jeanne Dubroca, Daniele Gaudy, Michel Greff, Christian Jacques, Jocelyne Lafarge, Gilles Kezachian, Ronan Le Gall, Alex Pariente, Tiphaine Pinault, Michaël Bismuth, Nathalie Boyer-Darrigrand, Philippe Bretagnolle, Stephane Carpentier, Franck Cholet, Christian Theodore, Rémi Combes, Francois Combet, Christophe Delanoe, Stéphanie De Montigny, Denis Soudan, Olivier Fourdan, Gilles Minier, Jeanne Languepin, Jean Roche, Jean-Louis Ginies, Olivier Nouel, Philippe Petitgars, Edith Robin, Romain Hamm, Jean François Roques, Sylvie Roussin-Bretagne, Agnès Sénéjoux, Sophie Muron, Nicolas Bardoux, Philippe Berthelemy, Patrick Madonia, Bertrand Carles, Catherine Reynier, Emmanuel Cuillerier, Innocenti Dadamessi, Jacques Danis, Bernard Debenes, Nathalie Dubuc-Rey, Gilles Lesur, Pauline Jouet, Catherine Lenaerts, Marc Garret, Alexandra Mineur, Bernard Chabry, Francois Pigot, Valérie Rossi, Ruth Tennenbaum, Julien Salloum, Maurice Hakim Slaoui, Stéphane Mathieu, Valérie Papapietro, Sheila Viola, Alexis Bezet, Claude Altman, Alain Audan, Jean Calabet, Claude Masliah, Laurent Fayemendy, Marc Duruy, Benoit Gauffeny, Ludovic Helie, Kamran Imani, Raoul Janin-Manificat, Jean-Paul Galmiche, Anne Kerlirzin, Laurent Bedenne, Christophe Locher, Gilles Michaudel, Gilles Missonnier, Michel Rinaldi-Dovio, Jean-Michel Rouillon, Stéphane Ecuer, Arnaud Patenotte, Jean Ariel Bronstein, Vincent Baty, Michel Bougnol, Pierre Bourbon, Philippe Cerbelaud, Annick Chavaillon, Franck Boiffin, Béatrice Dubern, Isabelle Duval De Laguierce, Fernand Greco, Florence Bouhot, Philippe Godeberge, Brigitte Grandmaison, Pascal Gros, Guy Targues, Jacques Corallo, Jean Boutin, Jacques Guillan, Jean Pierre Barbieux, Isabelle Loury Lariviere, Henri Le Genissel, Henri Leroi, Marc Bellaiche, Marie-Claire Elie-Legrand, Michel Dapoigny, Philippe Denoyel, Patrice Pienkowski, Philippe Pouche, Marc Michel Saurfelt, Jean Marie Thorel, Thierry Piche, Bruno Travers, Patrick Tuvignon, Marc Zalcberg, Guy Boulay, Christophe Zamora, Joelle Samama, Etienne Ricotie, Patrice De Fleury, Francois Maille, Jean Louis Mougenel, Olivier Gonot, Jean Philippe Menat, Mehdi Kaassis, Francoise Lang, Laurent Abramowitz, Nathalie Ganne, Olivier Pecriaux, Jacques-Arnaud Seyrig, Iradj Sobhani, Thierry Parmentier, Antoine Van Nieuwenhuyse, Francois-Xavier Weber, André Glibert, Catherine Bineau, Bernard Canet, Catherine Collin, Frederic Cordet, David David Parlier, Dominique Carre, Annie Peytier, Francine Fein, Jerome Barouk, Jacques Dewannieux, Johannes Hartwig, Jean-Louis Jouve, Bertrand Laplane, Gilles Lascar, Christophe Legrand, Pierre Le Marchand, Marie Pierre Liebaert, Michele Terdiman-Pire, Naceur Abdelli, Dominique Neveu, Philippe De La Lande, Patrick De Saint Louvent, Cécile Pelatan, Agnès Petit, Martial Richecoeur, Frederic Texier, Jean Brice Cazals, Bertrand Tissot, Christian Mourrut, Marie Doubremelle, Marc Foltz, Florence Gautier-Jubé, Jacques Martin, Elie Khouri, Thierry Lons, Martine Carlier-Bandu, Jean-Luc Monnin, Hervé Roche, Bernard Willemin, Xavier Houard, Abdelaziz Fatisse, Michèle Algard, Kamel Arab, Isabelle Borel, Cécile Lagarrigue, Ariane Chryssostalis, Dominique Boutroux, Jean-Pierre Dupuychaffray, Saïd Khaddari, François Mion, Thierry Puy-Montbrun, Jean-Philippe Girardet, Bruno Gury, Alain Landau, Monique Le Bihan, Sandrine Nieuviarts, Jean Ollivry, Philippe Le Bourgeois, Marie-Astrid Piquet, Michel -Pierre Escartin, Remi Systchenko, Franck Venezia, Michel Wantiez, Xavier Lesage, Elie Zrihen, Philippe Aygalenq, Barbara Dieumegard, Bernard Savarieau, Philippe Bulois, Stéphane Cattan, Jean-Lucien Diez, Olivier Fauchot, Eric Durous, Valérie Gazut, Christian Guilleminet, Jean-Marc Bories, Isabelle Joly Le Floch, Jean-Paul Vove, Stéphane Lelouch, Philippe Lévy, François Lhopital, Norma Marcato, Marianne Mozer-Bernardeau, Jean-Baptiste Nousbaum, Philippe Cattan, Alain Plane, Jean-Michel Raymond, Gilles Roseau, Gerald Rozental, Christian Boustière, Corinne Bonny, Mariepierre Cordier-Collet, Laurent Courat, Bernard Croguennec, Karine Delaunay- Tardy, Damien Labarriere, Edmond Geagea, Frédéric Gottrand, Eve Gelsi, Gerard Thiefin, Eric Wohlschies, Mathieu Miguet, Philippe Ponsot, Jean Suzanne, Yves Teste, Anne-Claire Dupont Gossart, Jean-Luc Baroni, Benabdallah Benchaa, Georges Blanc, Bernard Maroy, Philippe Bonjean, Catherine Brézault, Laure Bridoux-Henno, Claude Chayette, Dominique Auby, Robert Fiorucci, Georges Galindo, Gilles Hubert, Gilles Bonneau, Evelyne Marinier, Michele Pouteau, Afchine Alamdari, Bruno Delbende, Patrick Chamouard, Pascale D'Abravanel, Hélène Dall'Osto, Sophie Hervé, Jean Lefebvre, Damien Levoir, Philippe Lillo, Michel Rouch, Muriel Mathonnet, Mercédes De Lustrac, François-Jean Ramond, Bernard Roupret, and Alain Soupison
Subjects: Adult, Male, medicine.medical_specialty, Adolescent, Colorectal cancer, Population, Risk Assessment, Gastroenterology, Inflammatory bowel disease, Young Adult, 03 medical and health sciences, 0302 clinical medicine, Crohn Disease, Risk Factors, Internal medicine, medicine, Humans, Anal cancer, education, Aged, education.field_of_study, Crohn's disease, Hepatology, Rectal Neoplasms, business.industry, Incidence, Cancer, Odds ratio, Middle Aged, Anus Neoplasms, medicine.disease, Ulcerative colitis, Case-Control Studies, 030220 oncology & carcinogenesis, Female, 030211 gastroenterology & hepatology, France, business, Follow-Up Studies
Abstract: Background & Aims Little is known about the magnitude of the risk of anal and rectal cancer in patients with anal and/or perineal Crohn's disease. We aimed to assess the risk of anal and rectal cancer in patients with Crohn's perianal disease followed up in the Cancers Et Surrisque Associe aux Maladies Inflammatoires Intestinales En France (CESAME) cohort. Methods We collected data from 19,486 patients with inflammatory bowel disease (IBD) enrolled in the observational CESAME study in France, from May 2004 through June 2005; 14.9% of participants had past or current anal and/or perianal Crohn's disease. Subjects were followed up for a median time of 35 months (interquartile range, 29–40 mo). To identify risk factors for anal cancer in the total CESAME population, we performed a case-control study in which participants were matched for age and sex. Results Among the total IBD population, 8 patients developed anal cancer and 14 patients developed rectal cancer. In the subgroup of 2911 patients with past or current anal and/or perianal Crohn's lesions at cohort entry, 2 developed anal squamous-cell carcinoma, 3 developed perianal fistula–related adenocarcinoma, and 6 developed rectal cancer. The corresponding incidence rates were 0.26 per 1000 patient-years for anal squamous-cell carcinoma, 0.38 per 1000 patient-years for perianal fistula–related adenocarcinoma, and 0.77 per 1000 patient-years for rectal cancer. Among the 16,575 patients with ulcerative colitis or Crohn's disease without anal or perianal lesions, the incidence rate of anal cancer was 0.08 per 1000 patient-years and of rectal cancer was 0.21 per 1000 patient-years. Among factors tested by univariate conditional regression (IBD subtype, disease duration, exposure to immune-suppressive therapy, presence of past or current anal and/or perianal lesions), the presence of past or current anal and/or perianal lesions at cohort entry was the only factor significantly associated with development of anal cancer (odds ratio, 11.2; 95% CI, 1.18-551.51; P = .03). Conclusions In an analysis of data from the CESAME cohort in France, patients with anal and/or perianal Crohn's disease have a high risk of anal cancer, including perianal fistula–related cancer, and a high risk of rectal cancer.
Published: 2018

222. The nucleus of comet C/1983 H1 IRAS-Araki-Alcock

Author: Olivier Groussin, Philippe Lamy, Laurent Jorda, 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: Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, Infrared, Astronomy, Astronomy and Astrophysics, Astrophysics, Spin axis, 01 natural sciences, Photometry (optics), Astron, medicine.anatomical_structure, Heat flux, 13. Climate action, Space and Planetary Science, Geometric albedo, 0103 physical sciences, medicine, Spherical nucleus, 010303 astronomy & astrophysics, Nucleus, 0105 earth and related environmental sciences
Abstract: International audience; We present a synthetic analysis of all available infrared (2-20 mu m) and radio (1.3-6.1 cm) observations of comet C/1983 H1 IRAS-Araki-Alcock performed during its close approach to Earth in May 1983. We implement a model based on a spherical nucleus with a macroscopic mosaic of small and numerous active and inactive regions, and take into account the strong phase effect in the calculations of the thermal flux (often neglected in past interpretations). The orientation of the spin axis is assumed to be that determined by Sekanina [1988. Astron. J. 95, 1876-1894]. Additional constraints coming from visible photometry, measurements of the water production rate and the temporal variations of the cometary activity are introduced. We derive an equivalent nucleus radius of 3.4 +/- 0.5 km, consistent with a geometric albedo of 0.04 +/- 0.01 and a phase coefficient beta = 0.04 mag deg(-1) in the visible, and an active fraction of 2.9 +/- 1.9%. Although the nucleus is probably elongated as found in the past (Sekanina, 1988), we show that the relevant measurements were likely contaminated by the contribution of a variable coma. (C) 2010 Elsevier Ltd. All rights reserved.
Published: 2010

223. PHOTOMETRIC STUDY OF THE KREUTZ COMETS OBSERVED BYSOHOFROM 1996 TO 2005

Author: Michael F. A'Hearn, Philippe Lamy, G. Faury, Douglas P. Hamilton, D. A. Biesecker, Antoine Llebaria, Matthew M. Knight, Lowell Observatory [Flagstaff], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, NOAA Space Weather Prediction Center (SWPC), National Oceanic and Atmospheric Administration (NOAA), 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: Physics, Brightness, 010504 meteorology & atmospheric sciences, comets: general, Astronomy, Astronomy and Astrophysics, Astrophysics, Light curve, Solar maximum, methods: data analysis, 01 natural sciences, Photometry (optics), techniques: photometric, comets: individual: Kreutz Group, Space and Planetary Science, 0103 physical sciences, [INFO]Computer Science [cs], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: We present analysis of the photometry of more than 900 Kreutz comets observed by SOHO from 1996 to 2005. The Kreutz comets have "sungrazing" orbits with q ≈ 1-2 R� , high inclinations (i ≈ 143 ◦ ), and periods of 500-1000 years. We find that they do not have a bimodal distance of peak brightness as previously reported, but instead peak from 10.5 Rto 14 R� (prior to perihelion), suggesting there is a continuum of compositions rather than two distinct subpopulations. The light curves have two rates of brightening, typically ∝ r −7.3±2.0 when first observed by SOHO (at distances of 30-35 R� ) then rapidly transitioning to ∝ r −3.8±0.7 between 20 Rand 30 R� . It is unclear at what distance the steeper slope begins, but it likely does not extend much beyond the SOHO field of view. We derive nuclear sizes up to ∼50 m in radius for the SOHO-observed comets, with a cumulative size distribution of N(>R) ∝ R −2.2 for comets larger than 5 m in radius. This size distribution cannot explain the largest members of the family seen from the ground, suggesting that either the size distribution does not extend to the largest sizes or that the distribution is not uniform around the orbit. The total mass of the distribution up to the largest expected size (∼500 m) is ∼4 × 10 14 g, much less than the estimated masses of the largest ground-observed members. After correcting for the changing discovery circumstances, the flux of comets reaching perihelion has increased since 1996, and the increase is seen in comets of all sizes. Comparison of the SOHO comets with the Solwind and Solar Maximum Mission discoveries suggests there may have been an overabundance of bright comets arriving from 1979 to 1989, possibly indicative of a changing distribution around the Kreutz orbit.
Published: 2010

224. 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

225. Three-Dimensional Kinematics of Coronal Mass Ejections from STEREO/SECCHI-COR2 Observations in 2007 – 2008

Author: Antoine Llebaria, Philippe Lamy, and Yannick Boursier
Subjects: Physics, 3D reconstruction, Astronomy and Astrophysics, Astrophysics, Space weather, Tracking (particle physics), Corona, Computational physics, Acceleration, Space and Planetary Science, Physics::Space Physics, Trajectory, Coronal mass ejection, Radiance, Astrophysics::Solar and Stellar Astrophysics
Abstract: We present a new method to perform the three dimensional characterization of coronal mass ejections (CMEs) using stereoscopic images obtained with the STEREO/SECCHI-COR2 coronagraphs. Two approaches are proposed, and each associated algorithm gives the trajectory of the CME and its kinematical properties (velocity and acceleration profiles) intended for space weather forecast. The first approach is based on forward modeling appropriate to the reconstruction of surfaces in an optically thin medium, and performs a local approximation of the observed CME by a hemispherical shell, thus tracking the leading edge of the event. The second approach is based on tracking the center of gravity of the radiance of the CME in the images. More than 16 000 blind tests have been performed to assess the performance of each algorithm. For that purpose, we used three distinct libraries of simulated images of CMEs that correspond to three CME models: hemispherical shell, flux rope, and cloud-like. The two methods are applied to a set of CMEs observed in 2007 and 2008 by the SECCHI-COR2 coronagraphs, and when possible, our results are compared to those already published. The determinations of the direction of propagation and of the velocity are generally found in good agreement.
Published: 2009

226. Genes Involved in Human Ribosome Biogenesis are Transcriptionally Upregulated in Colorectal Cancer

Author: Karin Birkenkamp-Demtröder, Francisco Mansilla, Torben F. Ørntoft, and Philippe Lamy
Subjects: DNA binding site, Multidisciplinary, Downregulation and upregulation, Ribosome biogenesis, Promoter, Biology, Ribosomal RNA, RRNA processing, Gene, Molecular biology, Transcription factor
Abstract: Microarray gene expression profiling comprising 168 colorectal adenocarcinomas and 10 normal mucosas showed that over 79% of the genes involved in human ribosome biogenesis are significantly upregulated ( log 2 > 0.5 , p 10 − 3 ) when compared to normal mucosa. Overexpression was independent of microsatellite status. The promoters of the genes studied showed a significant enrichment for several transcription factor binding sites. There was a significant correlation between the number of binding site targets for these transcription factors and the observed gene transcript upregulation. The upregulation of rRNA processing genes points towards a coordinated process enabling the overproduction of matured ribosomal structures.
Published: 2009

227. Spitzer Space Telescope observations of the nucleus of comet 67P/Churyumov-Gerasimenko

Author: John Stansberry, I. Toth, Michael S. P. Kelley, Laurent Jorda, Olivier Groussin, and Philippe Lamy
Subjects: Physics, Effective radius, Photometry (astronomy), Spitzer Space Telescope, Space and Planetary Science, Point source, Comet, Astronomy, Astronomy and Astrophysics, Context (language use), Astrophysics, Albedo, Light curve
Abstract: Context. Comet 67P/Churyumov-Gerasimenko is the target of the Rosetta mission, and an early characterization of its nucleus is required to assist in preparing the orbital strategy of the spacecraft, the delivery of the Philae surface module and the science operations. We detected the nucleus using the Hubble Space Telescope in March 2003, but had to assume an albedo to derive its size from its observed magnitudes. Aims. It is important to derive an additional constraint for independently determining both the comet size and albedo. Methods. We implemented the well-known “radiometric method”, which combines visible and infrared photometry. Sixteen thermal images of 67P/C-G were obtained by the Multiband Imaging Photometer (MIPS) 24 μ m channel of the Spitzer Space Telescope (SST) on 25 February 2004: the observations spanned a time interval of ~12.5 h, which sampled the rotational light curve of its nucleus. The comet was then outbound at a heliocentric distance of 4.48 AU, at a distance of 4.04 AU from SST, and at a solar phase angle of 12.1°. The nucleus conspicuously appeared as a bright point source superimposed on a dust trail; it was necessary to apply the point-spread function fitting technique using an adequate model of the trail to correctly determine the thermal flux from the nucleus. The data were analyzed using a standard thermal model that incorporated the thermal inertia. Results. Our preferred solution with a low thermal inertia has overall dimensions measured along the principal axis of 4.40–5.20 km, 4.16–4.30 km, and 3.40–3.50 km, corresponding to an effective radius of a sphere with the same volume in the range of 1.93–2.03 km. Larger values of thermal inertia produce larger sizes but the effective radius cannot exceed ~2.3 km. The albedo is in the range 0.039–0.043, remarkably consistent with the canonical value of 0.04 for cometary nuclei. The success of the landing of the Philae surface module remains critically dependent upon the bulk density of the nucleus: it would be safe if close to 0.35 g cm-3 , but a larger value, for instance 0.5 g cm-3 , would present some risks.
Published: 2008

228. Asteroid 2867 Steins

Author: Olivier Groussin, Philippe Lamy, Jorge Márcio Carvano, I. Toth, M. Fulchignoni, Laurent Jorda, Sonia Fornasier, E. Dotto, M. A. Barucci, 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), 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), 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), Université Paris Cité (UPCité), Observatório Nacional/MCTI, INAF-Osservatorio Astronomico di Roma (INAF-OAR), and Konkoly Observatory, Research Center for Astronomy and Earth Sciences
Subjects: Physics, Rotation period, Effective radius, Infrared, Astronomy, Astronomy and Astrophysics, Astrophysics, Spitzer Space Telescope, Space and Planetary Science, Planet, Geometric albedo, Asteroid, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectrograph
Abstract: International audience; Context: Asteroid 2867 Steins is the first target of the Rosetta space mission with a flyby scheduled in September 2008. Aims: An early characterization is needed to optimize the flyby parameters and the science operations, and to maximize the scientific return. Methods: We used the infrared spectrograph (IRS) of the Spitzer Space Telescope (SST) to obtain 14 spectra ranging from 5.2 to 38.0 mum, and to sample the rotational period of the asteroid. The observations were performed on 22 November 2005, when the asteroid was 2.13 AU from the Sun, 1.60 AU from the SST, and at a phase angle of 27.2°. They were interpreted using a standard thermal model incorporating the thermal inertia. Results: The solution for a spherical shape leads to an effective radius rn = 2.46 ± 0.20 km and a thermal inertia I = 150 ± 60 J K-1 m-2 s-1/2, for a beaming factor between 0.8 and 1.0. The geometric albedo is then constrained by visible photometry to pR = 0.31 ± 0.05 and pV = 0.27 ± 0.04 when using a linear phase function. The H-G phase law, which includes an opposition effect, leads to larger values of the albedo, p_R(H-G) = 0.40 ± 0.07 and p_V(H-G) = 0.34 ± 0.06. The solution for our 3-dimensional shape model has overall dimensions of 5.73 ± 0.52 × 4.95 ± 0.45 × 4.58 ± 0.41 km.
Published: 2008

229. Prevalence ofMycoplasma genitalium, Mycoplasma hominisandChlamydia trachomatisAmong Danish Patients Requesting Abortion

Author: Gunna Christiansen, Jens Fedder, Svend Birkelund, Malene Hvid, Philippe Lamy, and Agata Baczynska
Subjects: Adult, DNA, Bacterial, Denmark, Urology, Immunoblotting, Chlamydia trachomatis, Enzyme-Linked Immunosorbent Assay, Mycoplasma genitalium, Mycoplasma hominis, Abortion, medicine.disease_cause, Polymerase Chain Reaction, law.invention, Microbiology, Pregnancy, law, Prevalence, medicine, Humans, Mycoplasma Infections, Sex organ, Polymerase chain reaction, biology, business.industry, Age Factors, Genitalia, Female, Chlamydia Infections, medicine.disease, biology.organism_classification, Antibodies, Bacterial, Virology, Abortion Applicants, Carriage, Reproductive Medicine, Abortion, Legal, Female, business
Abstract: The aim of the study was to determine lower genital tract carriage rate of Mycoplasma genitalium (M. genitalium) and to compare it to the carriage rates of Mycoplasma hominis (M. hominis ) and Chlamydia trachomatis (C. trachomatis) among 102 women requesting termination of pregnancy at the Horsens Hospital in Denmark. Real-Time PCR was used for the detection of bacterial DNA, and the presence of antibodies to the three microorganisms was determined by ELISA and immunoblotting. Real-Time PCR detected M. genitalium in one swab sample (0.98%) only, while the prevalence of C. trachomatis was high (15.69%) and M. hominis colonization (18.63%) was similar to colonization observed among sexually experienced adults. There was a significant difference in prevalence of M. hominis infection in the different age groups. C. trachomatis load in the cervical samples was significantly higher among young patients. There was no correlation between the presence of genital infection with C. trachomatis and genital mycoplasmas and no correlation between the presence of antibodies to these bacteria. In conclusion, in Danish patients it is not necessary to test for M. genitalium before abortion since less than 1% were found positive. The prevalence of genital C. trachomatis infections was high among the abortion-seeking patients.
Published: 2008

230. Velocity Profiles in the Solar Corona from Multi‐Instrument Observations

Author: Rosine Lallement, Dimitra Koutroumpa, Philippe Lamy, Eric Quémerais, Service d'aéronomie (SA), 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), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Mass flux, 010504 meteorology & atmospheric sciences, Terminal velocity, Solar wind, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Solar radius, Astrophysics, 01 natural sciences, 7. Clean energy, Acceleration, Interplanetary scintillation, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Physics, Astrophysics (astro-ph), Astronomy and Astrophysics, Space and Planetary Science, Physics::Space Physics, Corona, Outflow, Astrophysics::Earth and Planetary Astrophysics, Interplanetary spaceflight, Interplanetary medium
Abstract: We present a method to derive outflow velocities in the solar corona using different data sets including solar wind mass flux coming from the SWAN/SOHO instrument, electron density values from LASCO-C2 and interplanetary solar wind velocities derived from ground-based Interplanetary Scintillation Observations (IPS). In a first step, we combine the LASCO electron densities at 6 solar radii and the IPS velocities, and compare the product to the SWAN mass fluxes. It is found that this product represents the actual mass flux at 6 solar radii for the fast wind, but not for the slow wind. In regions dominated by the slow wind, the fluxes derived from SWAN are systematically smaller. This is interpreted as a proof that the fast solar wind has reached its terminal velocity at about 6 solar radii and expands with constant velocity beyond this distance. On the contrary, the slow solar wind has reached only half of its terminal value and is thus accelerated further out. In a second step, we combine the LASCO-C2 density profiles and the SWAN flux data to derive velocity profiles in the corona between 2.5 and 6 solar radii. Such profiles can be used to test models of the acceleration mechanism of the fast solar wind., 18 pages, 5 figues
Published: 2007

231. The long-term evolution and initial size of comets 46P/Wirtanen and 67P/Churyumov-Gerasimenko

Author: Giovanni B. Valsecchi, Olivier Groussin, R. Gonczi, Gerhard Hahn, and Philippe Lamy
Subjects: 67P/Churyumov-Gerasimenko, Physics, Orbital elements, 46P/Wirtanen, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, Radius, Upper and lower bounds, Term (time), Spherical model, Space and Planetary Science, Planet, Erosion, comets
Abstract: We present a new method to study the long-term evolution of cometary nuclei in order to estimate their original size, and we consider the case of comets 46P/Wirtanen (hereafter 46P) and 67P/Churyumov-Gerasimenko (hereafter 67P). We calculate the past evolution of the orbital elements of both comets over 100000 yr using a Bulirsch-Stoer integrator and over 450 000 yr using a Radau integrator, and we incorporate a realistic model of the erosion of their nucleus. Their long-term orbital evolution is prominently chaotic, resulting from several close encounters with planets, and this result is independent of the choice of the integrator and of the presence or not of non-gravitational forces. The dynamical lifetime of comet 46P is estimated at ∼133 000 yr and that of comet 67P at ∼105 000 yr. Our erosion model assumes a spherical nucleus composed of a macroscopic mixture of two thermally decoupled components, dust and pure water ice. Erosion strongly depends upon the active fraction and the density of the nucleus. It mainly takes place at heliocentric distances
Published: 2007

232. A Portrait of the Nucleus of Comet 67P/Churyumov-Gerasimenko

Author: Mikko Kaasalainen, Laurent Jorda, Björn Davidsson, Pedro J. Gutiérrez, Stephen C. Lowry, Imre Toth, Olivier Groussin, and Philippe Lamy
Subjects: Effective radius, Physics, Solar System, Axial ratio, Retrograde motion, Comet, Astronomy, Astronomy and Astrophysics, Astrophysics, Light curve, medicine.anatomical_structure, Space and Planetary Science, Geometric albedo, medicine, Nucleus
Abstract: In 2003, comet 67P/Churyumov–Gerasimenko was selected as the new target of the Rosetta mission as the most suitable alternative to the original target, comet 46P/Wirtanen, on the basis of orbital considerations even though very little was known about the physical properties of its nucleus. In a matter of a few years and based on highly focused observational campaigns as well as thorough theoretical investigations, a detailed portrait of this nucleus has been established that will serve as a baseline for planning the Rosetta operations and observations. In this review article, we present a novel method to determine the size and shape of a cometary nucleus: several visible light curves were inverted to produce a size–scale free three–dimensional shape, the size scaling being imposed by a thermal light curve. The procedure converges to two solutions which are only marginally different. The nucleus of comet 67P/Churyumov–Gerasimenko emerges as an irregular body with an effective radius (that of the sphere having the same volume) = 1.72 km and moderate axial ratios a/b = 1.26 and a/c = 1.5 to 1.6. The overall dimensions measured along the principal axis for the two solutions are 4.49–4.75 km, 3.54–3.77 km and 2.94–2.92 km. The nucleus is found to be in principal axis rotation with a period = 12.4–12.7 h. Merging all observational constraints allow us to specify two regions for the direction of the rotational axis of the nucleus: RA = 220°+50° −30° and Dec = −70° ± 10° (retrograde rotation) or RA = 40°+50° -30° and Dec = +70°± 10° (prograde), the better convergence of the various determinations presently favoring the first solution. The phase function, although constrained by only two data points, exhibits a strong opposition effect rather similar to that of comet 9P/Tempel 1. The definition of the disk–integrated albedo of an irregular body having a strong opposition effect raises problems, and the various alternatives led to a R-band geometric albedo in the range 0.045–0.060, consistent with our present knowledge of cometary nuclei. The active fraction is low, not exceeding ~ 7% at perihelion, and is probably limited to one or two active regions subjected to a strong seasonal effect, a picture coherent with the asymmetric behaviour of the coma. Our slightly downward revision of the size of the nucleus of comet 67P/Churyumov-Gerasimenko resulting from the present analysis (with the correlative increase of the albedo compared to the originally assumed value of 0.04), and our best estimate of the bulk density of 370 kg m−3, lead to a mass of ~ 8 × 1012 kg which should ease the landing of Philae and insure the overall success of the Rosetta mission.
Published: 2007

233. OSIRIS – The Scientific Camera System Onboard Rosetta

Author: Marco Fulle, K.-P. Wenzel, Fritz Gliem, A. López, Jean-Pierre Sivan, Rafael Rodrigo, Detlef Koschny, U. Telljohann, Nicolas Thomas, G. Parzianello, Kjetil Dohlen, R. Muller, K. Stöckner, Michael Küppers, Gian Paolo Guizzo, Giampiero Naletto, J. J. López-Moreno, Werner Curdt, J.-R. Kramm, V. Timon, Mirco Zaccariotto, D. Germerott, P. Ramous, Francesco Angrilli, Joseph A. Burns, M. Angulo, K.-U. Reiche, M. D. Michelena, Sonia Fornasier, T. Wittrock, M. Reina, Marco Pertile, H. U. Keller, Michael F. A'Hearn, A. Sanz, C. Quintana, Luisa Lara, A. Llebaria, Wing-Huen Ip, Laurent Jorda, L. Sabau, Peter Barthol, M. E. Bailey, Harald Michalik, Gérard Rousset, Stubbe F. Hviid, I. Büttner, José María Bermúdez de Castro, Hans Rickman, Gabriele Cremonese, Alain Origne, Holger Sierks, Stefano Debei, Roberto Ragazzoni, M. De Cecco, A. Lopez-Jimenez, Jean-Loup Bertaux, Cesare Barbieri, V. Brown, M. A. Barucci, J.-L. Boit, J. E. Rodriguez, Philippe Lamy, R. Meller, G. Bianchini, V. Da Deppo, J. Tabero, Ekkehard Kührt, G. Tomasch, 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), 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), Department of Astronomy and Space Physics [Uppsala], Uppsala University, Instituto de Astrofísica de Andalucía (IAA), 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), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Instituto Nacional de Técnica Aeroespacial (INTA), Armagh Observatory [Armagh], 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), Service d'aéronomie (SA), 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), Cornell University [New York], 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), University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Institut für Datentechnik und Kommunikationsnetze, Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Carlo Gavazzi Space SpA (CGS), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Universidad Politécnica de Madrid (UPM), Observatoire de Haute-Provence (OHP), Institut Pythéas (OSU PYTHEAS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Agence Spatiale Européenne = European Space Agency (ESA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), 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), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Cornell University, and Technische Universität Braunschweig [Braunschweig]
Subjects: 010504 meteorology & atmospheric sciences, Comet, Cometary activity, Coma (optics), Spectroscopic, Osiris, 7. Clean energy, 01 natural sciences, Aeronáutica, Data processing system, SOLAR-SYSTEM, Imaging system, comet, WIDE-ANGLE CAMERA, Shutter, Rosetta, 0103 physical sciences, SOUTHERN SPECTROPHOTOMETRIC STANDARDS, Angular resolution, Wide angle camera, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Remote sensing, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Physics, camera system, Spacecraft, biology, business.industry, Detector, Astronomy, Astronomy and Astrophysics, biology.organism_classification, COMET HALLEY, Narrow angle camera, Space and Planetary Science, DUST JETS, Camera, business
Abstract: The Optical, Spectroscopic, and Infrared Remote Imaging System OSIRIS is the scientific camera system onboard the Rosetta spacecraft (Figure 1). The advanced high performance imaging system will be pivotal for the success of the Rosetta mission. OSIRIS will detect 67P/Churyumov-Gerasimenko from a distance of more than 106 km, characterise the comet shape and volume, its rotational state and find a suitable landing spot for Philae, the Rosetta lander. OSIRIS will observe the nucleus, its activity and surroundings down to a scale of ~2 cm px−1. The observations will begin well before the onset of cometary activity and will extend over months until the comet reaches perihelion. During the rendezvous episode of the Rosetta mission, OSIRIS will provide key information about the nature of cometary nuclei and reveal the physics of cometary activity that leads to the gas and dust coma. OSIRIS comprises a high resolution Narrow Angle Camera (NAC) unit and a Wide Angle Camera (WAC) unit accompanied by three electronics boxes. The NAC is designed to obtain high resolution images of the surface of comet 67P/Churyumov-Gerasimenko through 12 discrete filters over the wavelength range 250–1000 nm at an angular resolution of 18.6 μrad px−1. The WAC is optimised to provide images of the near-nucleus environment in 14 discrete filters at an angular resolution of 101 μrad px−1. The two units use identical shutter, filter wheel, front door, and detector systems. They are operated by a common Data Processing Unit. The OSIRIS instrument has a total mass of 35 kg and is provided by institutes from six European countries. The support of the national funding agencies of Germany (DLR), France (CNES), Italy (ASI), Sweden (SNSB), and Spain (MEC) is gratefully acknowledged. Substantial support for the development of the Data Processing Unit was provided by the ESA Technical Directorate through the Technical Research Programme. In addition to the formal co-authors of this paper (comprising lead scientists, Co-Is, project managers, and lead engineers ), the project was supported by an enormous number of scientists, engineers, and technicians involved in the day-to-day development of the hardware. These include J. C. Blanc, D. Pouliquen, M. Saisse (France), A. Alvarez, A. L. Arteaga, A. Carretero, M. Fernández, H. Guerrero, P. Gutiérrez, J. L. Lizondo, V. Luengo, J. A. Martín, M. A. Martín, J. Meseguer, J. M. Mi, L. Moreno, J. Navarro, A. Núñez, E. Ragel, D. Rodríguez, G. Rosa, A. Sanchez, J. C. Sanmartín, G. Tonellotto (Spain), W. Boogaerts, W. Engelhardt, K. Eulig, B. Fiethe, A. Fischer, M. Gartner, K. Grabig, K. Kellner, A. Kiihn. W. Kiihn. J. Knollenberg, W. Neumann, J. Nitsch, P. Rüffer, H. Schüddekopf, U. Schiihlc. I. Sebastian, S. Stelzer, U. Strohmeyer, T. Tzscheetzsch, M. Wassermeyer (Germany), B. Johlander (ESTEC), M. Baessato, P. F. Brunello, S. Casotto, F. Don-, M. Lazzarin, E. Marchetti, F. Marzari, P. G. Nicolosi, F. Perón, F. Rampazzi, B. Saggin, G. Tondello, S. Verani, P. Zambolin ' (Italy), J. Lagerros, and B. Davidsson (Sweden). Peerreview
Published: 2007

234. Rotational state of the nucleus of Comet 9P/Tempel 1: Results from Hubble Space Telescope observations in 2004

Author: Harold A. Weaver, Imre Toth, Michael F. A'Hearn, Philippe Lamy, and Laurent Jorda
Subjects: Rotation period, Physics, Effective radius, Phase angle (astronomy), Space and Planetary Science, Magnitude (astronomy), Comet, Astronomy, Astronomy and Astrophysics, Coma (optics), Astrophysics, Light curve, Advanced Camera for Surveys
Abstract: The nucleus of Comet 9P/Tempel 1 was first observed with the Hubble Space Telescope (HST) in December 1997 [Lamy, P., Toth, I., A'Hearn, M.F., Weaver, H., Weissman, P.R., 2001. Icarus 154, 337–344], but the temporal coverage was insufficient to determine its rotational period. Because the success of the Deep Impact mission was critically dependent on understanding the rotational state and approximate shape and size of the nucleus, we extensively re-observed 9P/Tempel 1, this time with the Advanced Camera for Surveys (HST/ACS), from May 7.9 to 9.5, 2004 (UT). At the mid-point of the observing window, the comet was 3.52 AU from the Sun, 4.03 AU from the Earth, and at a solar phase angle of 13.3°. The program was comprised of 18 separate visits, each one corresponding to an HST orbit filled with 3 ACS exposures of either 800 or 857 s duration with the F606W broadband filter. These very deep exposures revealed a star-like object, without any apparent coma. The light curve, defined by 49 data points, is characterized by a mean apparent V magnitude of 21.8 and an amplitude of 0.5 mag, indicating that we were viewing the varying cross-section of a rotating, elongated body. The periodicity was analyzed with seven different techniques yielding a rotational period in the range 39.40 to 43.00 h, and a mean value of 41.27 ± 1.85 h (1 σ ). Using an albedo p V = 0.04 and a linear phase law with a coefficient β = 0.0465 mag deg −1 , we determined an effective radius of 3.01 km; a possible prolate spheroid solution has semi-axes a = 3.71 km , b = 2.36 km and a minimum axial ratio a / b ∼ 1.57 . By comparing the light curves obtained in 1997 and in 2004, we were able to constrain the phase function of the nucleus. Finally, an upper limit of A f ρ 0.04 cm is set based on the non-detection of the coma.
Published: 2007

235. Design status of ASPIICS, an externally occulted coronagraph for PROBA-3

Author: Andres Alia, Jim Van der Meulen, Giuseppe Massone, Michał Mosdorf, Jean-Sébastien Servaye, Russell A. Howard, Michał Ładno, Joe Zender, Jean-Philippe A. Halain, Vít Lédl, Gianalfredo Nicolini, Serge Koutchmy, Carl Jackson, Mauro Focardi, Adrian Dinescu, Steve Buckley, Yvan Stockman, Gerardo Capobianco, Raluca Muller, Karel Patočka, Rafal Graczyk, Jean-Marie Gillis, Konrad Grochowski, Jan Rautakoski, Radek Peresty, Radek Lapáček, Antonios Paschalis, Camille Galy, Jacek Kosiec, Etienne Renotte, Radek Melich, Dominique Mollet, Aline Hermans, Radoslav Darakchiev, Kanaris Tsinganos, Tomáš Vít, Nico Van Vooren, Miroslaw Rataj, Michal Kurowski, Richard Desselle, Alessandro Bemporad, Marcin Darmetko, Tomasz Górski, Lucas Salvador, Estelle Graas, Damien Galano, Arkadiusz Swat, Vladimir Daniel, Łukasz Mosdorf, Piotr Orleanski, Mateusz Mroczkowski, Irina Popescu, Lieve de Vos, Pavel Psota, Roman Rybecký, Cristina Bramanti, Hubert Kasprzyk, Ileana Cernica, Cédric Thizy, Joseph Bernier, Jana Kovačičinová, Philippe Lamy, Brian McGarvey, Andrei Zhukov, Alicja Zarzycka, Maurizio Pancrazzi, Arnaud Debaize, Cornel Solomon, Davide Loreggia, Tomasz Walczak, Federico Landini, Karl Fleury-Frenette, Kevin O'Neill, Agnes Mestreau-Garreau, Michel Thome, François Denis, Marie-Catherine Palau, Bogdan Nicula, N. Kranitis, Sylvie Liébecq, A. Fumel, Emmanuel Janssen, Marco Romoli, Silvano Fineschi, and ITA
Subjects: Physics, Spacecraft, Solar eclipse, business.industry, Astronomy, Space weather, Solar physics, Corona, law.invention, law, Coronal mass ejection, business, Coronagraph, Eclipse, Remote sensing
Abstract: The "sonic region" of the Sun corona remains extremely difficult to observe with spatial resolution and sensitivity sufficient to understand the fine scale phenomena that govern the quiescent solar corona, as well as phenomena that lead to coronal mass ejections (CMEs), which influence space weather. Improvement on this front requires eclipse-like conditions over long observation times. The space-borne coronagraphs flown so far provided a continuous coverage of the external parts of the corona but their over-occulting system did not permit to analyse the part of the white-light corona where the main coronal mass is concentrated. The proposed PROBA-3 Coronagraph System, also known as ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun), with its novel design, will be the first space coronagraph to cover the range of radial distances between ~1.08 and 3 solar radii where the magnetic field plays a crucial role in the coronal dynamics, thus providing continuous observational conditions very close to those during a total solar eclipse. PROBA-3 is first a mission devoted to the in-orbit demonstration of precise formation flying techniques and technologies for future European missions, which will fly ASPIICS as primary payload. The instrument is distributed over two satellites flying in formation (approx. 150m apart) to form a giant coronagraph capable of producing a nearly perfect eclipse allowing observing the sun corona closer to the rim than ever before. The coronagraph instrument is developed by a large European consortium including about 20 partners from 7 countries under the auspices of the European Space Agency. This paper is reviewing the recent improvements and design updates of the ASPIICS instrument as it is stepping into the detailed design phase.
Published: 2015

236. Mid-Term Quasi-Periodicities and Solar Cycle Variation of the White-Light Corona from 18.5 Years (1996.0-2014.5) of LASCO Observations

Author: Tatiana Barlyaeva, A. Llebaria, Philippe Lamy, 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: Solar minimum, Physics, Sunspot, 010504 meteorology & atmospheric sciences, Solar cycle 23, Astronomy and Astrophysics, Solar cycle 22, Atmospheric sciences, Solar maximum, 01 natural sciences, Corona, Solar cycle, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Physics::Space Physics, Coronal mass ejection, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract: International audience; We report on the analysis of the temporal evolution of the solar corona based on 18.5 years (1996.0 -aEuro parts per thousand 2014.5) of white-light observations with the SOHO/LASCO-C2 coronagraph. This evolution is quantified by generating spatially integrated values of the K-corona radiance, first globally, then in latitudinal sectors. The analysis considers time series of monthly values and 13-month running means of the radiance as well as several indices and proxies of solar activity. We study correlation, wavelet time-frequency spectra, and cross-coherence and phase spectra between these quantities. Our results give a detailed insight on how the corona responds to solar activity over timescales ranging from mid-term quasi-periodicities (also known as quasi-biennial oscillations or QBOs) to the long-term 11 year solar cycle. The amplitude of the variation between successive solar maxima and minima (modulation factor) very much depends upon the strength of the cycle and upon the heliographic latitude. An asymmetry is observed during the ascending phase of Solar Cycle 24, prominently in the royal and polar sectors, with north leading. Most prominent QBOs are a quasi-annual period during the maximum phase of Solar Cycle 23 and a shorter period, seven to eight months, in the ascending and maximum phases of Solar Cycle 24. They share the same properties as the solar QBOs: variable periodicity, intermittency, asymmetric development in the northern and southern solar hemispheres, and largest amplitudes during the maximum phase of solar cycles. The strongest correlation of the temporal variations of the coronal radiance - and consequently the coronal electron density - is found with the total magnetic flux. Considering that the morphology of the solar corona is also directly controlled by the topology of the magnetic field, this correlation reinforces the view that they are intimately connected, including their variability at all timescales.
Published: 2015

237. DENSITY AND CHARGE OF PRISTINE FLUFFY PARTICLES FROM COMET 67P/CHURYUMOV–GERASIMENKO

Author: Nicolas Altobelli, J. M. Jeronimo, Martin Hilchenbach, Philippe Lamy, Sihane Merouane, F. Lucarelli, M. Herranz, Mark Leese, Bo Å. S. Gustafson, M. Cosi, Stavro Ivanovski, Eberhard Grün, Vito Mennella, Jose Luis Ortiz, M. Ferrari, V. V. Zakharov, A. Lopez-Jimenez, Ernesto Palomba, Paul R. Weissman, Alessandra Rotundi, Roberto Sordini, Luigi Colangeli, R. Morales, J. E. Rodriguez, A. Molina, Mario Accolla, Francesca Esposito, V. Della Corte, Rafael Rodrigo, F. Giovane, J. A. M. McDonnell, J. J. López-Moreno, E. Mazzotta Epifani, Marco Fulle, John C. Zarnecki, Antal Juhász, F. Moreno, Pasquale Palumbo, E. Bussoletti, Simon F. Green, Karoly Szego, INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Universita degli studi di Napoli 'Parthenope' [Napoli], Planetary Science Institute [Tucson] (PSI), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Wigner Research Centre for Physics [Budapest], Hungarian Academy of Sciences (MTA), 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), INAF - Osservatorio Astronomico di Capodimonte (OAC), INAF - Osservatorio Astrofisico di Catania (OACT), Max-Planck-Institut für Sonnensystemforschung (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), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Max-Planck-Institut für Kernphysik (MPIK), British Geological Survey [Edinburgh], British Geological Survey (BGS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Leonardo, Virginia Polytechnic Institute and State University [Blacksburg], University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), 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 Space Astronomy Centre (ESAC), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: Physics, [PHYS]Physics [physics], Brightness, individual (67P/Churyumov-Gerasimenko) - space vehicles, Comet, Astronomy, Astronomy and Astrophysics, Coma (optics), general - comets, Astrophysics, Bulk density, 13. Climate action, Space and Planetary Science, instruments, comets, Negative potential, Formation and evolution of the Solar System, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Refractory (planetary science), ComputingMilieux_MISCELLANEOUS, Cosmic dust
Abstract: The Grain Impact Analyzer and Dust Accumulator (GIADA) instrument on board ESA’s Rosetta mission is constraining the origin of the dust particles detected within the coma of comet 67 P/Churyumov–Gerasimenko (67P). The collected particles belong to two families: (i) compact particles (ranging in size from 0.03 to 1 mm), witnessing the presence of materials that underwent processing within the solar nebula and (ii) fluffy aggregates (ranging in size from 0.2 to 2.5 mm) of sub-micron grains that may be a record of a primitive component, probably linked to interstellar dust. The dynamics of the fluffy aggregates constrain their equivalent bulk density to -3. These aggregates are charged, fragmented, and decelerated by the spacecraft negative potential and enter GIADA in showers of fragments at speeds -1. The density of such optically thick aggregates is consistent with the low bulk density of the nucleus. The mass contribution of the fluffy aggregates to the refractory component of the nucleus is negligible and their coma brightness contribution is less than 15%.
Published: 2015

238. Temporal morphological changes in the Imhotep region of comet 67P/Churyumov-Gerasimenko

Author: Ekkehard Kührt, Simone Marchi, Björn Davidsson, M. A. Barucci, Olivier Groussin, Cecilia Tubiana, Sonia Fornasier, M. De Cecco, Matteo Massironi, Ivano Bertini, Nilda Oklay, Giampiero Naletto, Stubbe F. Hviid, Wing-Huen Ip, Laurent Jorda, Michael Küppers, Monica Lazzarin, Marco Fulle, C. Güttler, V. Da Deppo, Holger Sierks, Jean-Loup Bertaux, Mohamed Ramy El-Maarry, J. J. Lopez Moreno, Gabriele Cremonese, Antoine Pommerol, Pedro J. Gutiérrez, Rafael Rodrigo, Hans Rickman, J. B. Vincent, Géza Kovács, Philippe Lamy, M. F. A Hearn, Maurizio Pajola, J. Knollenberg, Stefano Debei, H. U. Keller, Detlef Koschny, Nicolas Thomas, Stephen C. Lowry, Stefano Mottola, J.-R. Kramm, Francesco Marzari, Sebastien Besse, Luisa Lara, A.-T. Auger, Imre Tóth, Cesare Barbieri, 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), Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), International Space Science Institute [Bern] (ISSI), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), 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], 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, 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), Department of Industrial Engineering [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern], INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), 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), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), INAF - Osservatorio Astronomico di Padova (OAPD), 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), 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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, DEU, and ESP
Subjects: 010504 meteorology & atmospheric sciences, Comet, FOS: Physical sciences, Astrophysics, 01 natural sciences, Observational period, Comets: individual: 67P/Churyumov-Gerasimenko – Comets: general – Methods: data analysis, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Astronomy and Astrophysics, Space and Planetary Science, 0103 physical sciences, skin and connective tissue diseases, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), biology, biology.organism_classification, 13. Climate action, Sublimation (phase transition), sense organs, Osiris, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, Astrophysics - Earth and Planetary Astrophysics
Abstract: We report on the first major temporal morphological changes observed on the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, in the smooth terrains of the Imhotep region. We use images of the OSIRIS cameras onboard Rosetta to follow the temporal changes from 24 May 2015 to 11 July 2015. The morphological changes observed on the surface are visible in the form of roundish features, which are growing in size from a given location in a preferential direction, at a rate of 5.6 - 8.1$\times$10$^{-5}$ m s$^{-1}$ during the observational period. The location where changes started and the contours of the expanding features are bluer than the surroundings, suggesting the presence of ices (H$_2$O and/or CO$_2$) exposed on the surface. However, sublimation of ices alone is not sufficient to explain the observed expanding features. No significant variations in the dust activity pattern are observed during the period of changes., 4 pages, 3 figures; Letter for Astronomy and Astrophysics: accepted
Published: 2015

239. The morphological diversity of comet 67P/Churyumov-Gerasimenko

Author: Mohamed Ramy El-Maarry, Michael Küppers, Monica Lazzarin, M. Antonella Barucci, Hans Rickman, Jean-Baptiste Vincent, Holger Sierks, Francesco Angrilli, J. Rainer Kramm, Detlef Koschny, Maurizio Pajola, Simone Marchi, Frank Preusker, Nicolas Thomas, Sebastien Besse, A.-T. Auger, Giampiero Naletto, Olivier Groussin, Fiorangela La Forgia, Richard Moissl, Wing-Huen Ip, Laurent Jorda, Frank Scholten, J. Knollenberg, Cecilia Tubiana, L. Sabau, K. P. Wenzel, Mariolino De Cecco, Rafael Rodrigo, Nilda Oklay, Michael F. A'Hearn, Pedro J. Gutiérrez, Colin Snodgrass, Sonia Fornasier, Luisa Lara, Sara Magrin, Francesca Ferri, B. J. R. Davidsson, Antoine Pommerol, Jean-Loup Bertaux, Francesco Marzari, H. U. Keller, Matteo Massironi, Philippe Lamy, Jessica Agarwal, Vania Da Deppo, Stubbe F. Hviid, Ekkehard Kührt, Jose J. Lopez Moreno, Harald Michalik, Cesare Barbieri, Carsten Güttler, Dennis Bodewits, Stefano Mottola, Gabriele Cremonese, Marco Fulle, Stefano Debei, Lorenza Giacomini, Ivano Bertini, Physikalisches Institut [Bern], Universität Bern [Bern], 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), 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, Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), DLR Institute of Planetary Research, German Aerospace Center (DLR), 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), European Space Agency (ESA), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Università degli Studi di Trento (UNITN), Department of Industrial Engineering [Padova], INAF - Osservatorio Astronomico di Trieste (OAT), Dipartimento di Geoscienze [Padova], 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), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), Instituto Nacional de Técnica Aeroespacial (INTA), 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), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Agence Spatiale Européenne = European Space Agency (ESA), ITA, USA, GBR, FRA, and DEU
Subjects: Insolation, Multidisciplinary, Spacecraft, Pixel, business.industry, Infrared, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], comet 67P, Mass wasting, morphological diversity, Astrobiology, 67P/Churyomov-Gerasimenko, 13. Climate action, morphology, Rosetta, OSIRIS, Surface dust, business, Geology, Remote sensing
Abstract: International audience; Images of comet 67P/Churyumov-Gerasimenko acquired by the OSIRIS (Optical, Spectroscopic and Infrared Remote Imaging System) imaging system onboard the European Space Agency’s Rosetta spacecraft at scales of better than 0.8 meter per pixel show a wide variety of different structures and textures. The data show the importance of airfall, surface dust transport, mass wasting, and insolation weathering for cometary surface evolution, and they offer some support for subsurface fluidization models and mass loss through the ejection of large chunks of material.
Published: 2015

240. Search for satellites near comet 67P/Churyumov-Gerasimenko using Rosetta/OSIRIS images

Author: F. La Forgia, Ivano Bertini, Nilda Oklay, Francesco Marzari, Wing-Huen Ip, Laurent Jorda, Sonia Fornasier, V. Da Deppo, Michael Küppers, Marco Fulle, Michael F. A'Hearn, J. L. Bertaux, Jörg Knollenberg, Olivier Groussin, Lorenza Giacomini, Carsten Güttler, R. Rodrigo, Harald Michalik, Horst Uwe Keller, Hans Rickman, J. B. Vincent, Maurizio Pajola, M. De Cecco, Sara Magrin, Cesare Barbieri, L. M. Lara, B. J. R. Davidsson, Ekkehard Kührt, Stefano Debei, Philippe Lamy, Gabriele Cremonese, Detlef Koschny, Nicolas Thomas, J. J. Lopez Moreno, J.-R. Kramm, Holger Sierks, Monica Lazzarin, Cecilia Tubiana, Matteo Massironi, F. Moreno, Stubbe F. Hviid, P. J. Gutiérrez, Stefano Mottola, M. A. Barucci, Giampiero Naletto, Francesca Ferri, Jessica Agarwal, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), 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 Industrial Engineering [Padova], University of Trento [Trento], Université Paris Diderot - Paris 7 (UPD7), INAF - Osservatorio Astronomico di Trieste (OAT), Dipartimento di Geoscienze [Padova], DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, DEU, ESP, Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), Consiglio Nazionale delle Ricerche [Roma] (CNR), 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: Physics, Comets: individual: 67P/Churyumov-Gerasimenko, 67P/Churyumov-Gerasimenko, Solar System, Comet tail, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Context (language use), Astronomy and Astrophysics, Comets: general, Planets and satellites: detection, Techniques: photometric, Astrophysics, Photometry, 13. Climate action, Space and Planetary Science, Comet nucleus, Interstellar comet, Hill sphere, Comets, Satellite, Small bodies - Comets - satellites - Rosetta OSIRIS
Abstract: International audience; The European Space Agency Rosetta mission reached and started escorting its main target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, at the beginning of August 2014. Within the context of solar system small bodies, satellite searches from approaching spacecraft were extensively used in the past to study the nature of the visited bodies and their collisional environ- ment.Aims. During the approaching phase to the comet in July 2014, the OSIRIS instrument onboard Rosetta performed a campaign aimed at detecting objects in the vicinity of the comet nucleus and at measuring these objects’ possible bound orbits. In addition to the scientific purpose, the search also focused on spacecraft security to avoid hazardous material in the comet’s environment.Methods. Images in the red spectral domain were acquired with the OSIRIS Narrow Angle Camera, when the spacecraft was at a distance between 5 785 km and 5 463 km to the comet, following an observational strategy tailored to maximize the scientific outcome. From the acquired images, sources were extracted and displayed to search for plausible displacements of all sources from image to image. After stars were identified, the remaining sources were thoroughly analyzed. To place constraints on the expected displacements of a potential satellite, we performed Monte Carlo simulations on the apparent motion of potential satellites within the Hill sphere.Results. We found no unambiguous detections of objects larger than ∼ 6 m within ∼ 20 km and larger than ∼ 1 m between ∼ 20 km and ∼ 110 km from the nucleus, using images with an exposure time of 0.14 s and 1.36 s, respectively. Our conclusions are consistent with independent works on dust grains in the comet coma and on boulders counting on the nucleus surface. Moreover, our analysisArticle number, page 1 of 9 shows that the comet outburst detected at the end of April 2014 was not strong enough to eject large objects and to place them intoa stable orbit around the nucleus. Our findings underline that it is highly unlikely that large objects survive for a long time around cometary nuclei.
Published: 2015

241. Large heterogeneities in comet 67P as revealed by active pits from sinkhole collapse

Author: Frank Scholten, Michael Küppers, Pedro J. Gutiérrez, M. Antonella Barucci, Maurizio Pajola, Sebastien Besse, Cesare Barbieri, Sonia Fornasier, Nilda Oklay, Dennis Bodewits, Stephen C. Lowry, J. Knollenberg, Gábor L. Kovács, N. M. Hoekzema, Vania Da Deppo, Carsten Güttler, A.-T. Auger, Zhong-Yi Lin, Robert Gaskell, Ivano Bertini, Lorenza Giacomini, Imre Tóth, H. U. Keller, Marco Fulle, Rafael Rodrigo, Stefano Mottola, Francesca Ferri, P. Gutierrez-Marques, Detlef Koschny, Nicolas Thomas, Michael F. A'Hearn, Jessica Agarwal, Claire Capanna, Simone Marchi, Jean-Loup Bertaux, Wing-Huen Ip, Lucie Maquet, Laurent Jorda, Fiorangela La Forgia, Richard Moissl, Francesco Marzari, C. Leyrat, Harald Michalik, Monica Lazzarin, Jean-Baptiste Vincent, Mariolino De Cecco, Sara Magrin, B. J. R. Davidsson, Giampiero Naletto, Luisa Lara, Philippe Lamy, Holger Sierks, Cecilia Tubiana, S. Höfner, Stefano Debei, Jose J. Lopez Moreno, Vicky Lee, Gabriele Cremonese, Ekkehard Kührt, Aurelie Guilbert-Lepoutre, Olivier Groussin, Matteo Massironi, Stubbe F. Hviid, Mohamed Ramy El-Maarry, Hans Rickman, Frank Preusker, R. Kramm, 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, 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), 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), 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, 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), 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), Department of Industrial Engineering [Padova], University of Trento [Trento], Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Planetary Science Institute [Tucson] (PSI), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institute of aging, Udall Parkinson's research center, University of Pennsylvania, School of Physical Sciences [Canterbury], University of Kent [Canterbury], Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Dipartimento di Geoscienze [Padova], Institut für Datentechnik und Kommunikationsnetze, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Max-Planck-Institut für Sonnensystemforschung (MPS), European Space Agency (ESA)-European Space Agency (ESA), Universita degli Studi di Padova, Consiglio Nazionale delle Ricerche [Roma] (CNR), Universität Bern [Bern], University of Pennsylvania [Philadelphia], ITA, USA, GBR, FRA, and DEU
Subjects: geography, Multidisciplinary, geography.geographical_feature_category, Sinkhole, Comet, 67P/CHURYUMOV-GERASIMENKO ACTIVITY, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mineralogy, Geomorphology, comet 67P, CAMERA, Spatial distribution, Asteroids, Kuiper belt, Astrobiology, Impact crater, 13. Climate action, Asteroid, comets, Rosetta mission, 9P/TEMPEL 1, DEEP IMPACT, Geology
Abstract: International audience; Pits have been observed on many cometary nuclei mapped by spacecraft1, 2, 3, 4. It has been argued that cometary pits are a signature of endogenic activity, rather than impact craters such as those on planetary and asteroid surfaces. Impact experiments5, 6 and models7, 8 cannot reproduce the shapes of most of the observed cometary pits, and the predicted collision rates imply that few of the pits are related to impacts8, 9. Alternative mechanisms like explosive activity10 have been suggested, but the driving process remains unknown. Here we report that pits on comet 67P/Churyumov–Gerasimenko are active, and probably created by a sinkhole process, possibly accompanied by outbursts. We argue that after formation, pits expand slowly in diameter, owing to sublimation-driven retreat of the walls. Therefore, pits characterize how eroded the surface is: a fresh cometary surface will have a ragged structure with many pits, while an evolved surface will look smoother. The size and spatial distribution of pits imply that large heterogeneities exist in the physical, structural or compositional properties of the first few hundred metres below the current nucleus surface.
Published: 2015

242. Two independent and primitive envelopes of the bilobate nucleus of comet 67P

Author: Pedro J. Gutiérrez, Gábor L. Kovács, Nilda Oklay, Cesare Barbieri, Mariolino De Cecco, Emanuele Simioni, Maurizio Pajola, Harald Michalik, Francesco Marzari, Jörg Knollenberg, Gabriele Cremonese, Lorenza Giacomini, Olivier Groussin, Zhong-Yi Lin, Rafael Rodrigo, Ekkehard Kührt, R. Kramm, Michael Küppers, Holger Sierks, Dennis Bodewits, M. Antonella Barucci, Sonia Fornasier, Carsten Güttler, Robert Gaskell, Jean-Loup Bertaux, Wing-Huen Ip, Laurent Jorda, Ivano Bertini, Stefano Debei, Stephen C. Lowry, Stefano Mottola, Luisa Lara, Fiorangela La Forgia, Sebastien Besse, H. U. Keller, Antoine Pommerol, Mohamed Ramy El-Maarry, Vania Da Deppo, Matteo Massironi, Detlef Koschny, Claire Capanna, Nicolas Thomas, Stubbe F. Hviid, Hans Rickman, Francesca Ferri, Michael F. A'Hearn, Jessica Agarwal, Frank Preusker, A.-T. Auger, Giampiero Naletto, Marco Fulle, Frank Scholten, Sara Magrin, Philippe Lamy, Jose J. Lopez Moreno, Björn Davidsson, Cecilia Tubiana, Monica Lazzarin, Jean-Baptiste Vincent, Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Universita degli Studi di Padova, Dipartimento di Geoscienze [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), 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), Department of Information Engineering [Padova] (DEI), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Physikalisches Institut [Bern], Universität Bern [Bern], DLR Institute of Planetary Research, German Aerospace Center (DLR), Max-Planck-Institut für Sonnensystemforschung (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), 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], 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Agency (ESA)-European Space Agency (ESA), Department of Industrial Engineering [Padova], University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Planetary Science Institute [Tucson] (PSI), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institut für Datentechnik und Kommunikationsnetze, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), Technische Universität Braunschweig [Braunschweig], 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), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), ITA, USA, GBR, FRA, DEU, Università degli Studi di Padova = University of Padua (Unipd), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Agence Spatiale Européenne = European Space Agency (ESA), and Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: Physics, [PHYS]Physics [physics], Solar System, Multidisciplinary, 67P, 010504 meteorology & atmospheric sciences, 530 Physics, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Stratification (water), Astrophysics, bilobate nucleus, 500 Science, 01 natural sciences, Lobe, medicine.anatomical_structure, comet, Asteroid, 0103 physical sciences, medicine, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Nucleus, 0105 earth and related environmental sciences
Abstract: International audience; The factors shaping cometary nuclei are still largely unknown, but could be the result of concurrent effects of evolutionary and primordial processes. The peculiar bilobed shape of comet 67P/Churyumov-Gerasimenko may be the result of the fusion of two objects that were once separate or the result of a localized excavation by outgassing at the interface between the two lobes. Here we report that the comet's major lobe is enveloped by a nearly continuous set of strata, up to 650 metres thick, which are independent of an analogous stratified envelope on the minor lobe. Gravity vectors computed for the two lobes separately are closer to perpendicular to the strata than those calculated for the entire nucleus and adjacent to the neck separating the two lobes. Therefore comet 67P/Churyumov-Gerasimenko is an accreted body of two distinct objects with `onion-like' stratification, which formed before they merged. We conclude that gentle, low-velocity collisions occurred between two fully formed kilometre-sized cometesimals in the early stages of the Solar System. The notable structural similarities between the two lobes of comet 67P/Churyumov-Gerasimenko indicate that the early-forming cometesimals experienced similar primordial stratified accretion, even though they formed independently.
Published: 2015

243. Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the sun

Author: F. Lucarelli, Roberto Sordini, Stavro Ivanovski, Vito Mennella, Hans Rickman, M. Ferrari, Michael F. A'Hearn, Mark Leese, Vincenzo Della Corte, Bo Å. S. Gustafson, E. Bussoletti, Luisa Lara, Jean-Loup Bertaux, M. Antonietta Barucci, Laurent Jorda, Rafael Rodrigo, Ernesto Palomba, Dennis Bodewits, Philippe Lamy, Detlef Koschny, Stefano Debei, Paul R. Weissman, J. Knollenberg, Francesco Marzari, Jean-François Crifo, Nilda Oklay, Nicolas Thomas, Stephen C. Lowry, Marco Fulle, Carsten Güttler, H. U. Keller, L. Sabau, K. P. Wenzel, J. E. Rodriguez, Michael Küppers, Vladimir Zakharov, A. Molina, Pedro J. Gutiérrez, Gabriele Cremonese, F. Giovane, Cesare Barbieri, Mario Accolla, Antonio C. López-Jiménez, Sonia Fornasier, Francesco Angrilli, Ekkehard Kührt, Francesca Esposito, Harald Michalik, José Juan López-Moreno, Elena Mazzotta Epifani, Vania Da Deppo, Jessica Agarwal, José M. Jerónimo, Fernando Moreno, Eberhard Grün, M. Cosi, Ivano Bertini, Olivier Groussin, R. Morales, Pasquale Palumbo, Simon F. Green, Stubbe F. Hviid, Jose Luis Ortiz, R. Kramm, Alessandra Rotundi, John C. Zarnecki, Giampiero Naletto, J. Anthony M. McDonnell, Wing Ip, Mariolino De Cecco, Colin Snodgrass, Stefano Mottola, Jean-Marie Perrin, Luigi Colangeli, Nicolas Altobelli, Monica Lazzarin, Jean-Baptiste Vincent, Björn Davidsson, Cecilia Tubiana, M. Herranz, Holger Sierks, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Scienze e Tecnologie [Napoli] (DIST), Universita degli studi di Napoli 'Parthenope' [Napoli], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Trieste (OAT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (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), Department of Physics and Astronomy [Uppsala], Uppsala University, Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk (PAN), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig [Braunschweig], Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Akademie der Wissenschaften zu Göttingen, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Department of Industrial Engineering [Padova], 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), 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), INAF - Osservatorio Astronomico di Padova (OAPD), HEPPI - LATMOS, CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), 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), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], School of Physical Sciences [Canterbury], Institut für Datentechnik und Kommunikationsnetze, Departamento de Fisica Aplicada [Granada], Universidad de Granada (UGR), Department of Information Engineering [Padova] (DEI), Faculté d'Informatique [Namur], Facultés Universitaires Notre Dame de la Paix (FUNDP) - Namur, 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), Instituto Nacional de Técnica Aeroespacial (INTA), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, 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), NASA-California Institute of Technology (CALTECH), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], 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, HELIOS - LATMOS, 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), Facultés Universitaires Notre Dame de la Paix (FUNDP), Università degli Studi di Napoli 'Parthenope' = University of Naples (PARTHENOPE), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universidad de Granada = University of Granada (UGR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, genetic structures, Comet dust, Astronomical unit, comet 67P, coma, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, law.invention, Orbiter, comet, Planet, law, Rosetta, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Multidisciplinary, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Medicine (all), Astronomy, Mass ratio, Billion years, Accretion (astrophysics), 13. Climate action, Astrophysics::Earth and Planetary Astrophysics, dust, Formation and evolution of the Solar System
Abstract: Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astronomical units inbound, GIADA and OSIRIS (Optical, Spectroscopic, and Infrared Remote Imaging System) detected 35 outflowing grains of mass 10 −10 to 10 −7 kilograms, and 48 grains of mass 10 −5 to 10 −2 kilograms, respectively. Combined with gas data from the MIRO (Microwave Instrument for the Rosetta Orbiter) and ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instruments, we find a dust/gas mass ratio of 4 ± 2 averaged over the sunlit nucleus surface. A cloud of larger grains also encircles the nucleus in bound orbits from the previous perihelion. The largest orbiting clumps are meter-sized, confirming the dust/gas ratio of 3 inferred at perihelion from models of dust comae and trails.
Published: 2015

244. Astronomy

Author: F. La Forgia, Michael F. A'Hearn, Nilda Oklay, Stefano Mottola, Cecilia Tubiana, R. Kramm, Ivano Bertini, Jörg Knollenberg, Gabriele Cremonese, Jean-Loup Bertaux, R. Rodrigo, V. Da Deppo, Stefano Debei, Ekkehard Kührt, Stubbe F. Hviid, Francesco Marzari, L. M. Lara, Sonia Fornasier, P. J. Gutiérrez, Monica Lazzarin, Marco Fulle, Stephen C. Lowry, L. Sabau, K. P. Wenzel, Olivier Groussin, Hans Rickman, Horst Uwe Keller, Cesare Barbieri, Holger Sierks, Detlef Koschny, Nicolas Thomas, Maurizio Pajola, M. A. Barucci, Carsten Güttler, Colin Snodgrass, Giampiero Naletto, J. B. Vincent, Wing-Huen Ip, Laurent Jorda, Dennis Bodewits, M. De Cecco, Francesca Ferri, Jessica Agarwal, Sara Magrin, B. J. R. Davidsson, Michael Küppers, Francesco Angrilli, Philippe Lamy, Harald Michalik, J. J. Lopez Moreno, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), DLR Institute of Planetary Research, German Aerospace Center (DLR), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), 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', Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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 Physics and Astronomy [Uppsala], Uppsala University, Università degli Studi di Trento (UNITN), Department of Industrial Engineering [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), 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], 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), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Dipartimento di Fisica [Padova], Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), Instituto Nacional de Técnica Aeroespacial (INTA), Max-Planck-Institut für Sonnensystemforschung (MPS), Universita degli Studi di Padova, Universität Bern [Bern], Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), 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), European Space Agency (ESA)-European Space Agency (ESA), European Space Agency (ESA), ITA, USA, GBR, FRA, DEU, and ESP
Subjects: Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, North pole, Physics, COMET 67P/CHURYUMOV-GERASIMENKO, Brightness, comets: general – comets: individual: 67P/Churyumov-Gerasimenko, biology, 530 Physics, 520 Astronomy, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy, Narrow angle, Astrophysics, biology.organism_classification, 13. Climate action, Rosetta, Osiris, COMET 67P/CHURYUMOV-GERASIMENKO, Rosetta
Abstract: International audience; 67P/Churyumov-Gerasimenko is the target comet of the ESA’s Rosetta mission. After commissioning at the end of March 2014, the Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard Rosetta, started imaging the comet and its dust environment to investigate how they change and evolve while approaching the Sun.Methods. We focused our work on Narrow Angle Camera (NAC) orange images and Wide Angle Camera (WAC) red and visible-610 images acquired between 2014 March 23 and June 24 when the nucleus of 67P was unresolved and moving from approximately 4.3 AU to 3.8 AU inbound. During this period the 67P – Rosetta distance decreased from 5 million to 120 thousand km.Results. Through aperture photometry, we investigated how the comet brightness varies with heliocentric distance. 67P was likely already weakly active at the end of March 2014, with excess flux above that expected for the nucleus. The comet’s brightness was mostly constant during the three months of approach observations, apart from one outburst that occurred around April 30 and a second increase in flux after June 20. Coma was resolved in the profiles from mid-April. Analysis of the coma morphology suggests that most of the activity comes from a source towards the celestial north pole of the comet, but the outburst that occurred on April 30 released material in a different direction.
Published: 2015

245. Size-frequency distribution of boulders >=7 m on comet 67P/Churyumov-Gerasimenko

Author: Carsten Güttler, Sebastien Besse, Sara Magrin, Marco Fulle, Philippe Lamy, Frank Preusker, Cesare Barbieri, Jean-Loup Bertaux, Lorenza Giacomini, N. Thomas, Detlef Koschny, Olivier Groussin, Antoine Pommerol, Francesca Ferri, J.-C. Lee, Wing-Huen Ip, Laurent Jorda, Harald Michalik, José Juan López-Moreno, Maria Antonietta Barucci, H. U. Keller, Frank Scholten, Holger Sierks, Simone Marchi, Mohamed Ramy El-Maarry, Monica Lazzarin, Jessica Agarwal, Ivano Bertini, Hans Rickman, Jean-Bapiste Vincent, Michael F. A'Hearn, Nilda Oklay, Alice Lucchetti, Zhong-Yi Lin, Giampiero Naletto, Kürt Ekkehard, J. Rainer Kramm, Michael Küppers, Fiorangela La Forgia, Matteo Massironi, Björn Davidsson, Richard Moissl, Cecilia Tubiana, Stubbe F. Hviid, Maurizio Pajola, Vania Da Deppo, Mariolino De Cecco, Francesco Marzari, Sonia Fornasier, Stefano Mottola, Jörg Knollenberg, Rafael Rodrigo, Pedro J. Gutiérrez, Emanuele Simioni, L. M. Lara, A.-T. Auger, Stefano Debei, Gabriele Cremonese, 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, Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Dipartimento di Geoscienze [Padova], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Department of Industrial Engineering [Padova], Physikalisches Institut [Bern], Universität Bern [Bern], Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Operations Department (ESAC), European Space Astronomy Centre (ESAC), 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), 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), CNR Institute for Photonics and Nanotechnologies (IFN), Consiglio Nazionale delle Ricerche [Roma] (CNR), University of Trento [Trento], Université Paris Diderot - Paris 7 (UPD7), 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 Astronomy [Taiwan] (IANCU), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Institut für Datentechnik und Kommunikationsnetze, 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 [Spain] (CSIC), Polska Akademia Nauk (PAN), Technische Universität Braunschweig [Braunschweig], 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), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Università degli Studi di Padova = University of Padua (Unipd), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Universität Bern [Bern] (UNIBE), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), ITA, USA, GBR, FRA, and DEU
Subjects: 67P/Churyumov-Gerasimenko, Main lobe, Comet, Data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Narrow angle, Astrophysics, Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Methods: data analysis, Astronomy and Astrophysics, Space and Planetary Science, Size frequency, Rosetta, medicine, Comets, Physics, Number density, Cometary Science, Debris, Lobe, medicine.anatomical_structure, 13. Climate action, Drag
Abstract: Aims: We derive for the first time the size-frequency distribution of boulders on a comet, 67P/Churyumov-Gerasimenko (67P), computed from the images taken by the Rosetta/OSIRIS imaging system. We highlight the possible physical processes that lead to these boulder size distributions. Methods: We used images acquired by the OSIRIS Narrow Angle Camera, NAC, on 5 and 6 August 2014. The scale of these images (2.44-2.03 m/px) is such that boulders ≥7 m can be identified and manually extracted from the datasets with the software ArcGIS. We derived both global and localized size-frequency distributions. The three-pixel sampling detection, coupled with the favorable shadowing of the surface (observation phase angle ranging from 48° to 53°), enables unequivocally detecting boulders scattered all over the illuminated side of 67P. Results: We identify 3546 boulders larger than 7 m on the imaged surface (36.4 km2), with a global number density of nearly 100/km2 and a cumulative size-frequency distribution represented by a power-law with index of -3.6 +0.2/-0.3. The two lobes of 67P appear to have slightly different distributions, with an index of -3.5 +0.2/-0.3 for the main lobe (body) and -4.0 +0.3/-0.2 for the small lobe (head). The steeper distribution of the small lobe might be due to a more pervasive fracturing. The difference of the distribution for the connecting region (neck) is much more significant, with an index value of -2.2 +0.2/-0.2. We propose that the boulder field located in the neck area is the result of blocks falling from the contiguous Hathor cliff. The lower slope of the size-frequency distribution we see today in the neck area might be due to the concurrent processes acting on the smallest boulders, such as i) disintegration or fragmentation and vanishing through sublimation; ii) uplifting by gas drag and consequent redistribution; and iii) burial beneath a debris blanket. We also derived the cumulative size-frequency distribution per km2 of localized areas on 67P. By comparing the cumulative size-frequency distributions of similar geomorphological settings, we derived similar power-law index values. This suggests that despite the selected locations on different and often opposite sides of the comet, similar sublimation or activity processes, pit formation or collapses, as well as thermal stresses or fracturing events occurred on multiple areas of the comet, shaping its surface into the appearance we see today.
Published: 2015

246. On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko

Author: Carsten Güttler, Sara Magrin, Francesco Marzari, Jörg Knollenberg, Wing-Huen Ip, Francesca Ferri, Lorenza Giacomini, Philippe Lamy, Harald Michalik, Holger Sierks, Laurent Jorda, Rafael Rodrigo, C. Leyrat, N. M. Hoekzema, Monica Lazzarin, Frank Scholten, J. Rainer Kramm, Nilda Oklay, Detlef Koschny, Jean-Baptiste Vincent, Michael Küppers, Nicolas Thomas, Jessica Agarwal, L. Sabau, M. Antonella Barucci, Sebastien Besse, Mariolino De Cecco, Maurizio Pajola, Francesco Angrilli, Bjö Davidsson, Michael F. A'Hearn, Mirco Zaccariotto, Dennis Bodewits, Stefano Debei, Luisa Lara, Fiorangela La Forgia, Sonia Fornasier, Matteo Massironi, Vania Da Deppo, Richard Moissl, Stubbe F. Hviid, Jean-Loup Bertaux, Klaus Peter Wenzel, Jose J. Lopez Moreno, Marco Pertile, Cesare Barbieri, Gabriele Cremonese, Olivier Groussin, Ekkehard Kührt, Robert Gaskell, Ivano Bertini, Marco Fulle, Gábor L. Kovács, Hans Rickman, Martin Pätzold, H. U. Keller, Cecilia Tubiana, Pedro J. Gutiérrez, Frank Preusker, Stefano Mottola, Simone Marchi, P. Gutierrez-Marques, A.-T. Auger, Claire Capanna, Colin Snodgrass, Giampiero Naletto, 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), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-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], DLR Institute of Planetary Research, German Aerospace Center (DLR), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Akademie der Wissenschaften zu Göttingen, Department of Industrial Engineering [Padova], 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), 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), University of Trento [Trento], INAF - Osservatorio Astronomico di Trieste (OAT), Planetary Science Institute [Tucson] (PSI), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Institute of Astronomy [Taiwan] (IANCU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), European Space Astronomy Centre (ESAC), Solar System Exploration Research Virtual Institute (SSERVI), Southwest Research Institute [Boulder] (SwRI), Dipartimento di Geoscienze [Padova], Institut für Datentechnik und Kommunikationsnetze, Department of Information Engineering [Padova] (DEI), Instituto Nacional de Técnica Aeroespacial (INTA), Center for Space and Habitability (CSH), University of Bern, Physikalisches Institut [Bern], Universität Bern [Bern], Rhenish Institute for Environmental Research (RIU), University of Cologne, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Università degli Studi di Padova = University of Padua (Unipd), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), Agence Spatiale Européenne = European Space Agency (ESA), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Universität Bern [Bern] (UNIBE), ITA, USA, GBR, FRA, and DEU
Subjects: Physics, Multidisciplinary, 530 Physics, activity, Astronomical unit, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], comet 67P, Contact binary, Short neck, Astrophysics, Billion years, Nucleus, medicine.anatomical_structure, 67/P Churyumov-Gerasimenko, Rosetta, medicine, Sublimation (phase transition), comets, OSIRIS, nucleus strcutcure, Principal axis theorem
Abstract: International audience; mages from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen consistently. The nucleus rotates about the principal axis of momentum. The surface morphology suggests that the removal of larger volumes of material, possibly via explosive release of subsurface pressure or via creation of overhangs by sublimation, may be a major mass loss process. The shape raises the question of whether the two lobes represent a contact binary formed 4.5 billion years ago, or a single body where a gap has evolved via mass loss.
Published: 2015
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247. Large scale dust jets in the coma of 67P/Churyumov-Gerasimenko as seen by the OSIRIS instrument on board Rosetta

Author: P. J. Gutiérrez, P. Gutiérrez Marqués, F. La Forgia, Antoine Pommerol, Sonia Fornasier, J. J. López-Moreno, Nilda Oklay, Cesare Barbieri, Giampiero Naletto, A.-T. Auger, Marco Fulle, Holger Sierks, Monica Lazzarin, Jörg Knollenberg, M. A. Barucci, V. Da Deppo, Agata Rozek, Zhong-Yi Lin, Francesco Marzari, Ekkehard Kührt, Jean-Loup Bertaux, Mohamed Ramy El-Maarry, Rafael Rodrigo, Björn Davidsson, R. Moissl–fraund, Cecilia Tubiana, Hans Rickman, F. Moreno, Stubbe F. Hviid, Maurizio Pajola, Harald Michalik, Michael Küppers, Detlef Koschny, Nicolas Thomas, Sara Magrin, M. De Cecco, Ivano Bertini, Francesca Ferri, J.-R. Kramm, Géza Kovács, Philippe Lamy, Wing-Huen Ip, Jessica Agarwal, Stephen C. Lowry, Laurent Jorda, Michael F. A'Hearn, Luisa Lara, Carsten Güttler, Dennis Bodewits, Olivier Groussin, H. U. Keller, Stefano Debei, Gabriele Cremonese, Sebastien Besse, J. B. Vincent, Stefano Mottola, M. D. Sabau, Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], 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), 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), 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), 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), DLR Institute of Planetary Research, German Aerospace Center (DLR), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, DEU, ESP, 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), Consiglio Nazionale delle Ricerche [Roma] (CNR), and Universität Bern [Bern]
Subjects: Comets: general, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, 67P/Churyumov-Gerasimenko, 010504 meteorology & atmospheric sciences, Comet dust, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Coma (optics), Astrophysics, Rotation, 01 natural sciences, Comet nucleus, 0103 physical sciences, Rosetta, medicine, comets, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, biology, Comet tail, activity, Astronomy, biology.organism_classification, medicine.anatomical_structure, 13. Climate action, Osiris, Nucleus
Abstract: Context. During the most recent perihelion passage in 2009 of comet 67P/Churyumov-Gerasimenko (67P), ground-based observations showed an anisotropic dust coma where jet-like features were detected at ~ 1.3 AU from the Sun. The current perihelion passage is exceptional as the Rosetta spacecraft is monitoring the nucleus activity since March 2014, when a clear dust coma was already surrounding the nucleus at 4.3 AU from the Sun. Subsequently, the OSIRIS camera also witnessed an outburst in activity between April 27 and 30, and since mid-July, the dust coma at rh ~ 3.7-3.6 AU preperihelion is clearly non-isotropic, pointing to the existence of dust jet-like features. Aims: We aim to ascertain on the nucleus surface the origin of the dust jet-like features detected as early as in mid-July 2014. This will help to establish how the localized comet nucleus activity compares with that seen in previous apparitions and will also help following its evolution as the comet approaches its perihelion, at which phase most of the jets were detected from ground-based observations. Determining these areas also allows locating them in regions on the nucleus with spectroscopic or geomorphological distinct characteristics. Methods: Three series of dust images of comet 67P obtained with the Wide Angle Camera (WAC) of the OSIRIS instrument onboard the Rosetta spacecraft were processed with different enhancement techniques. This was made to clearly show the existence of jet-like features in the dust coma, whose appearance toward the observer changed as a result of the rotation of the comet nucleus and of the changing observing geometry from the spacecraft. The position angles of these features in the coma together with information on the observing geometry, nucleus shape, and rotation, allowed us to determine the most likely locations on the nucleus surface where the jets originate from. Results: Geometrical tracing of jet sources indicates that the activity of the nucleus of 67P gave rise during July and August 2014 to large-scale jet-like features from the Hapi, Hathor, Anuket, and Aten regions, confirming that active regions may be present on the nucleus localized at 60° northern latitude as deduced from previous comet apparitions. There are also hints that large-scale jets observed from the ground are possibly composed, at their place of origin on the nucleus surface, of numerous small-scale features.
Published: 2015

248. Morphology and dynamics of the jets of comet 67P/Churyumov-Gerasimenko: Early-phase development

Author: Gabriele Cremonese, Ekkehard Kührt, Stefano Debei, F. La Forgia, Cesare Barbieri, Mariolino De Cecco, Stefano Mottola, Michael F. A'Hearn, Stubbe F. Hviid, Nilda Oklay, Pedro J. Gutiérrez, Giampiero Naletto, José Juan López-Moreno, Wing-Huen Ip, Zhong-Yi Lin, Laurent Jorda, Michael Küppers, N. Thomas, Luisa Lara, Jean-Loup Bertaux, Maurizio Pajola, Stephen C. Lowry, Holger Sierks, Francesco Marzari, Harald Michalik, Yu-Te Liao, J.-R. Kramm, Dennis Bodewits, Géza Kovács, Sonia Fornasier, Björn Davidsson, Marco Fulle, Philippe Lamy, Detlef Koschny, Cecilia Tubiana, Jessica Agarwal, H. U. Keller, Jörg Knollenberg, Monica Lazzarin, Agata Rozek, Rafael Rodrigo, Maria Antonietta Barucci, Hans Rickman, Olivier Groussin, J.-C. Lee, Ivano Bertini, Jean-Baptste Vincent, Ian-Lin Lai, Carsten Güttler, Vania Da Deppo, Institute of Astronomy, National Taiwan University [Taiwan] (NTU), Space Science Institute [Macau] (SSI), Macau University of Science and Technology (MUST), Institute of Space Science [Taiwan], National Central University [Taiwan] (NCU), Department of Earth Sciences [Chung-Li City], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Instituto de Astrofísica de Andalucía (IAA), 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, 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), International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), 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], 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 Physics and Astronomy [Uppsala], Uppsala University, Department of Industrial Engineering [Padova], University of Trento [Trento], Université Paris Diderot - Paris 7 (UPD7), INAF - Osservatorio Astronomico di Trieste (OAT), DLR Institute of Planetary Research, German Aerospace Center (DLR), Centre for Astrophysics and Planetary Science [Canterbury] (CAPS), University of Kent [Canterbury], Department of Information Engineering [Padova] (DEI), Physikalisches Institut [Bern], Universität Bern [Bern], ITA, USA, GBR, FRA, DEU, ESP, 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 Universität Bern [Bern] (UNIBE)
Subjects: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, 530 Physics, Comet dust, Astrophysics::High Energy Astrophysical Phenomena, Comet, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Potential source, comets, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Comets: individual: 67P/Churyumov-Gerasimenko, Astronomy and Astrophysics, Space and Planetary Science, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astronomy, 13. Climate action, Sublimation (phase transition), Astrophysics::Earth and Planetary Astrophysics, Early phase
Abstract: Aims: The OSIRIS camera onboard the Rosetta spacecraft obtained close-up views of the dust coma of comet 67P. The jet structures can be used to trace their source regions and to examine the possible effect of gas-surface interaction. Methods: We analyzed the wide-angle images obtained in the special dust observation sequences between August and September 2014. The jet features detected in different images were compared to study their time variability. The locations of the potential source regions of some of the jets are identified by ray tracing. We used a ring-masking technique to calculate the brightness distribution of dust jets along the projected distance. Results: The jets detected between August and September 2014 mostly originated in the Hapi region. Morphological changes appeared over a timescale of several days in September. The brightness slope of the dust jets is much steeper than the background coma. This might be related to the sublimation or fragmentation of the emitted dust grains. Interaction of the expanding gas flow with the cliff walls on both sides of Hapi could lead to erosion and material down-fall to the nucleus surface. Appendix A is available in electronic form at "http://www.aanda.org/10.1051/0004-6361/201525961/olm"
Published: 2015

249. OSIRIS observations of meter-sized exposures of H2O ice at the surface of 67P/Churyumov-Gerasimenko and interpretation using laboratory experiments

Author: Stephen C. Lowry, F. La Forgia, Cesare Barbieri, Frank Preusker, Nilda Oklay, Antoine Pommerol, Steve Boudreault, Ivano Bertini, Monica Lazzarin, Stubbe F. Hviid, Géza Kovács, M. De Cecco, V. Da Deppo, M. A. Barucci, M. F. A'Hearn, Olivier Groussin, Holger Sierks, J.-R. Kramm, J. L. Lopez Moreno, J. L. Bertaux, P. J. Gutierrez, Marco Fulle, Carsten Güttler, Jessica Agarwal, Björn Davidsson, Frank Scholten, Detlef Koschny, Nicolas Thomas, Giampiero Naletto, Cecilia Tubiana, Harald Michalik, Philippe Lamy, Wing-Huen Ip, Laurent Jorda, Mohamed Ramy El-Maarry, Sonia Fornasier, Clement Feller, Olivier Poch, H. U. Keller, Bernhard Jost, Francesco Marzari, Hans Rickman, J. B. Vincent, Stefano Mottola, Raphael Marschall, Jörg Knollenberg, Maurizio Pajola, E. Küppers, A. Gracia-Berná, R. Rodrigo, Ekkehard Kührt, L. M. Lara, Gabriele Cremonese, Stefano Debei, A.-T. Auger, 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), 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), 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), Department of Physics and Astronomy [Uppsala], Uppsala University, 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), Dipartimento di Fisica e Astronomia 'Galileo Galilei', Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], DLR Institute of Planetary Research, German Aerospace Center (DLR), School of Physical Sciences [Canterbury], University of Kent [Canterbury], Department of Industrial Engineering [Padova], CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), 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), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), 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), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Institut für Datentechnik und Kommunikationsnetze, Universität Bern [Bern], Universita degli Studi di Padova, Max-Planck-Institut für Sonnensystemforschung (MPS), 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), IMPEC - LATMOS, Technische Universität Braunschweig [Braunschweig], Consiglio Nazionale delle Ricerche [Roma] (CNR), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), European Space Agency (ESA)-European Space Agency (ESA), Polska Akademia Nauk (PAN), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), ITA, USA, GBR, FRA, and DEU
Subjects: Physics, Brightness, Spots, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Techniques: image processing, Stratification (water), Astronomy and Astrophysics, Mass wasting, Astrophysics, Debris, Comets: general, Methods: laboratory: solid state, Space and Planetary Science, Image processing, 13. Climate action, Sublimation (phase transition), comets: general – techniques: image processing – methods: laboratory: solid state, comets, Visible spectrum
Abstract: International audience; Since OSIRIS started acquiring high-resolution observations of the surface of the nucleus of comet 67P/Churyumov-Gerasimenko, over one hundred meter-sized bright spots have been identified in numerous types of geomorphologic regions, but mostly located in areas receiving low insolation. The bright spots are either clustered, in debris fields close to decameter-high cliffs, or isolated without structural relation to the surrounding terrain. They can be up to ten times brighter than the average surface of the comet at visible wavelengths and display a significantly bluer spectrum. They do not exhibit significant changes over a period of a few weeks. All these observations are consistent with exposure of water ice at the surface of boulders produced by dislocation of the weakly consolidated layers that cover large areas of the nucleus. Laboratory experiments show that under simulated comet surface conditions, analog samples acquire a vertical stratification with an uppermost porous mantle of refractory dust overlaying a layer of hard ice formed by recondensation or sintering under the insulating dust mantle. The evolution of the visible spectrophotometric properties of samples during sublimation is consistent with the contrasts of brightness and color seen at the surface of the nucleus. Clustered bright spots are formed by the collapse of overhangs that is triggered by mass wasting of deeper layers. Isolated spots might be the result of the emission of boulders at low velocity that are redepositioned in other regions.
Published: 2015
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250. Shape model, reference system definition, and cartographic mapping standards for comet 67P/Churyumov-Gerasimenko. Stereo-photogrammetric analysis of Rosetta/OSIRIS image data

Author: Carsten Güttler, P. J. Gutiérrez, Giampiero Naletto, Holger Sierks, Cecilia Tubiana, Stefano Mottola, Michael Küppers, Harald Michalik, Jessica Agarwal, Michael F. A'Hearn, Detlef Koschny, Cesare Barbieri, Luisa Lara, Stubbe F. Hviid, J. L. Bertaux, Nicolas Thomas, M. De Cecco, Klaus-Dieter Matz, B. J. R. Davidsson, M. A. Barucci, Nilda Oklay, Monica Lazzarin, W-H. Ip, Philippe Lamy, Jean-Baptiste Vincent, Jörg Knollenberg, Thomas Roatsch, Olivier Groussin, Konrad Willner, Frank Scholten, V. Da Deppo, Laurent Jorda, Horst Uwe Keller, J.-R. Kramm, Francesco Marzari, Hans Rickman, J. J. Lopez Moreno, Rafael Rodrigo, Marco Fulle, Frank Preusker, Sonia Fornasier, Ivano Bertini, Gabriele Cremonese, Ekkehard Kührt, Stefano Debei, DLR Institute of Planetary Research, German Aerospace Center (DLR), 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), Instituto de Astrofísica de Andalucía (IAA), 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, Physikalisches Institut [Bern], Universität Bern [Bern], Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', Universita degli Studi di Padova, International Space Science Institute [Bern] (ISSI), Centro de Astrobiologia [Madrid] (CAB), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Research and Scientific Support Department, ESTEC (RSSD), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, 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), 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], Université Paris Diderot - Paris 7 (UPD7), INAF - Osservatorio Astronomico di Trieste (OAT), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Operations Department (ESAC), European Space Astronomy Centre (ESAC), Dipartimento di Fisica, Institut für Datentechnik und Kommunikationsnetze, ITA, USA, GBR, FRA, DEU, 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), Universität Bern [Bern] (UNIBE), 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), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: 67P/Churyumov-Gerasimenko, Comets: general, Planets and satellites: surfaces, Reference systems, Astronomy and Astrophysics, Space and Planetary Science, bulk density, 530 Physics, Comet, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, Position (vector), precession, Rosetta, Comets, cartography, OSIRIS, mapping, Remote sensing, shape model, Physics, biology, Orientation (computer vision), 520 Astronomy, Spherical coordinate system, biology.organism_classification, reference coordinate frame, rotational parameters, stereo-photogrammetry, Precession, Osiris, Longitude, Cartography, Reference frame
Abstract: We analyzed more than 200 OSIRIS NAC images with a pixel scale of 0.9-2.4 m/pixel of comet 67P/Churyumov-Gerasimenko (67P) that have been acquired from onboard the Rosetta spacecraft in August and September 2014 using stereo-photogrammetric methods (SPG). We derived improved spacecraft position and pointing data for the OSIRIS images and a high-resolution shape model that consists of about 16 million facets (2 m horizontal sampling) and a typical vertical accuracy at the decimeter scale. From this model, we derive a volume for the northern hemisphere of 9.35 km3 ± 0.1 km3. With the assumption of a homogeneous density distribution and taking into account the current uncertainty of the position of the comet's center-of-mass, we extrapolated this value to an overall volume of18.7 km3± 1.2 km3, and, with a current best estimate of 1.0 × 1013 kg for the mass, we derive a bulk density of 535 kg/m3± 35 kg/m3. Furthermore, we used SPG methods to analyze the rotational elements of 67P. The rotational period for August and September 2014 was determined to be 12.4041 ± 0.0004 h. For the orientation of the rotational axis (z-axis of the body-fixed reference frame) we derived a precession model with a half-cone angle of 0.14°, a cone center position at 69.54°/64.11° (RA/Dec J2000 equatorial coordinates), and a precession period of 10.7 days. For the definition of zero longitude (x-axis orientation), we finally selected the boulder-like Cheops feature on the big lobe of 67P and fixed its spherical coordinates to 142.35° right-hand-rule eastern longitude and -0.28° latitude. This completes the definition of the new Cheops reference frame for 67P. Finally, we defined cartographic mapping standards for common use and combined analyses of scientific results that have been obtained not only within the OSIRIS team, but also within other groups of the Rosetta mission. Appendices are available in electronic form at http://www.aanda.org
Published: 2015

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