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Refractory and semi-volatile organics at the surface of comet 67P/Churyumov-Gerasimenko: Insights from the VIRTIS/Rosetta imaging spectrometer

Quirico, E. and Moroz, Liubov and Schmitt, B. and Arnold, Gabriele and Faure, M. and Beck, P. and Bonal, L. and Ciarniello, M. and Capaccioni, F. and Filacchione, G. and Erard, S. and Leyrat, C. and Bockelee-Morvan, D. and Zinzi, A. and Palomba, E. and Drossart, P. and Tosi, F. and Capria, M. T. and De Sanctis, M.C. and Raponi, A. and Fonti, S. and Mancarella, F. and Orofino, V. and Barucci, M. A. and Blecka, M. and Carlson, R. W. and Despan, D. and Faure, A. and Fornasier, S. and Gudipati, M. and Longobardo, A and Markus, Kathrin and Mennella, V. and Merlin, F. and Piccioni, G. and Rousseau, Batiste and Taylor, F.W. (2016) Refractory and semi-volatile organics at the surface of comet 67P/Churyumov-Gerasimenko: Insights from the VIRTIS/Rosetta imaging spectrometer. Icarus, 272, pp. 32-47. Elsevier. doi: 10.1016/j.icarus.2016.02.028. ISSN 0019-1035.

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Official URL: http://dx.doi.org/10.1016/j.icarus.2016.02.028


The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument aboard the Rosetta spacecraft has performed extensive spectral mapping of the surface of comet 67P/Churyumov-Gerasimenko in the range 0.3-5 μm. The reflectance spectra collected across the surface display a low reflectance factor over the whole spectral range, two spectral slopes in the visible and near-infrared ranges and a broad absorption band centered at 3.2 μm. The first two of these characteristics are typical of dark small bodies of the Solar System and are difficult to interpret in terms of composition. Moreover, solar wind irradiation may modify the structure and composition of surface materials and there is no unequivocal interpretation of these spectra devoid of vibrational bands. To circumvent these problems, we consider the composition of cometary grains analyzed in the laboratory to constrain the nature of the cometary materials and consider results on surface rejuvenation and solar wind processing provided by the OSIRIS and ROSINA instruments, respectively. Our results lead to five main conclusions: (i) The low albedo of comet 67P/CG is accounted for by a dark refractory polyaromatic carbonaceous component mixed with opaque minerals. VIRTIS data do not provide direct insights into the nature of these opaque minerals. However, according to the composition of cometary grains analyzed in the laboratory, we infer that they consist of Fe-Ni alloys and FeS sulfides. (ii) A semi-volatile component, consisting of a complex mix of low weight molecular species not volatilized at T∼220 K, is likely a major carrier of the 3.2 μm band. Water ice contributes significantly to this feature in the neck region but not in other regions of the comet. COOH in carboxylic acids is the only chemical group that encompasses the broad width of this feature. It appears as a highly plausible candidate along with the NH4+ ion. (iii) Photolytic/thermal residues, produced in the laboratory from interstellar ice analogs, are potentially good spectral analogs. (iv) No hydrated minerals were identified and our data support the lack of genetic links with the CI, CR and CM primitive chondrites. This concerns in particular the Orgueil chondrite, previously suspected to have been of cometary origin. (v) The comparison between fresh and aged terrains revealed no effect of solar wind irradiation on the 3.2 μm band. This is consistent with the presence of efficient resurfacing processes such as dust transport from the interior to the surface, as revealed by the OSIRIS camera.

Item URL in elib:https://elib.dlr.de/107277/
Document Type:Article
Title:Refractory and semi-volatile organics at the surface of comet 67P/Churyumov-Gerasimenko: Insights from the VIRTIS/Rosetta imaging spectrometer
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Quirico, E.Laboratory of Planetology, CNRS Joseph Fourier UniversityUNSPECIFIEDUNSPECIFIED
Schmitt, B.Grenoble Planetology LaboratoryUNSPECIFIEDUNSPECIFIED
Faure, M.Universite Grenoble Alpes, CNRS, IPAG, Grenoble, FranceUNSPECIFIEDUNSPECIFIED
Beck, P.Laboratoire de Planétologie de Grenoble (LPG) - University Joseph Fourier Grenoble, Grenboble, FranceUNSPECIFIEDUNSPECIFIED
Bonal, L.Université Grenoble Alpes, CNRS, Institut de Planétologie et d’Astrophysique de Grenoble, Grenoble, FranceUNSPECIFIEDUNSPECIFIED
Bockelee-Morvan, D.Observatoire de Paris, MeudonUNSPECIFIEDUNSPECIFIED
Zinzi, A.Institute for Interplanetary Space Physics - INAF, Rome, ItalyUNSPECIFIEDUNSPECIFIED
Palomba, E.Institute for Interplanetary Space Physics - INAF, Rome, ItalyUNSPECIFIEDUNSPECIFIED
Drossart, P.Observatoire de Paris, Meudon, FranceUNSPECIFIEDUNSPECIFIED
Tosi, F.INAF-IASF Istituto di Astrofisica Spaziale e Fisica Cosmica, Roma ItalyUNSPECIFIEDUNSPECIFIED
Capria, M. T.Instituto di Astrofisica Spaziale e Fisica Cosmica, Roma, ItalyUNSPECIFIEDUNSPECIFIED
De Sanctis, M.C.Istituto Nazionale di Astrofisica, Rome, Italy.UNSPECIFIEDUNSPECIFIED
Fonti, S.Dipartimento di Fisica, Università di Lecce, ItalyUNSPECIFIEDUNSPECIFIED
Mancarella, F.Dipartimento di Matematica e Fisica "E. De Giorgi", Università del Salento, Lecce, ItalyUNSPECIFIEDUNSPECIFIED
Orofino, V.Universita degli Studi di LecceUNSPECIFIEDUNSPECIFIED
Barucci, M. A.Observatoire de Paris, Meudon, FranceUNSPECIFIEDUNSPECIFIED
Blecka, M.Polish Academi of Sciences, Warsaw, PolandUNSPECIFIEDUNSPECIFIED
Carlson, R. W.Jet Propulsion LaboratoryUNSPECIFIEDUNSPECIFIED
Despan, D.Laboratoire d’Etudes Spatiales et d’Instrumentation en Astrophysique, Observatoire de Paris/CNRS/Université Pierre et Marie Curie/Université Paris-Diderot, Meudon, FranceUNSPECIFIEDUNSPECIFIED
Faure, A.Universite Grenoble Alpes, CNRS, IPAG, Grenoble, FranceUNSPECIFIEDUNSPECIFIED
Fornasier, S.Observatoire de Paris-Meudon, FranceUNSPECIFIEDUNSPECIFIED
Gudipati, M.NASA Jet Propulsion Laboratory, Pasadena, CA 91109, USAUNSPECIFIEDUNSPECIFIED
Longobardo, AINAF-LAPS, Via del Fosso del Cavaliere 100, I-00133 Rome, ItalyUNSPECIFIEDUNSPECIFIED
Markus, KathrinWestfälische Wilhelms-Universität MünsterUNSPECIFIEDUNSPECIFIED
Taylor, F.W.University of OxfordUNSPECIFIEDUNSPECIFIED
Date:1 July 2016
Journal or Publication Title:Icarus
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 32-47
Keywords:Comets; Organic chemistry; Infrared observations; Meteorites; Spectrophotometry
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Space Exploration
DLR - Research theme (Project):R - Project ROSETTA Instruments (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Asteroids and Comets
Institute of Planetary Research > Leitungsbereich PF
Deposited By: Kappel, David
Deposited On:20 Nov 2017 15:56
Last Modified:06 Sep 2019 15:26

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