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Water and carbon dioxide ices-rich areas on comet 67P/CG nucleus surface

Filacchione, G. and Capaccioni, F. and Raponi, A. and Desanctis, M.C. and Ciarniello, M. and Barucci, M. A. and Tosi, F. and Migliorini, A. and Capria, M. T. and Erard, S. and Bockelee-Morvan, D. and Leyrat, C. and Arnold, Gabriele and Kappel, David and McCord, Thomas B. (2017) Water and carbon dioxide ices-rich areas on comet 67P/CG nucleus surface. In: Ices in the Solar System, pp. 1-2. Ices in the Solar System, 23-26 January 2017, Madrid, Spain.

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Official URL: https://www.cosmos.esa.int/web/ices-in-the-solar-system/programme

Abstract

So far, only two ice species have been identified by Rosetta/VIRTIS-M [1] on the surface of 67P/Churyumov-Gerasimenko during the pre-perihelion time: crystalline water and carbon dioxide ice. Water ice has been spectroscopically identified in three distinct modalities: 1) On the active areas of Hapi region where water ice changes its abundance with local time and illumination conditions, condensing during the night hours and sublimating during daytime [2]; 2) On recent debris fields collapsed from two elevated structures in the Imhotep region where more fresh and pristine material is exposed [3]; 3) On eight bright areas located in Khonsu, Imhotep, Anhur, Atum and Khepry regions [4] where single or multiple grouped icy patches with sizes ranging between few meters to about 60 m are observed. Carbon dioxide ice has been detected only in a 60-80 m area in Anhur region while it was exiting from a four year-long winter-night season [5]. This ice deposit underwent a rapid sublimation, disappearing in about one month after its initial detection. While water and carbon dioxide ice appear always mixed with the ubiquitous dark material [6,7], there are no evidences of the presence of water and carbon dioxide ices mixed together in the same area. If observed, ices always account for very small fraction (few percent) with respect to the dark material. Moreover, the surface ice deposits are preferentially located on the large lobe and the neck while they are absent on the small lobe. Apart from these differences in the spatial distribution of ices on the surface, a large variability is observed the mixing modalities and in the grain size distributions, as retrieved from spectral modeling [8]: 1) very small μm-sized water ice grains in intimate mixing with the dark terrain are detected on Hapi active regions [2]; 2) two monodispersed distributions with maxima at 56 μm and at 2 mm, corresponding to the intimate and areal mixing classes, are observed on the Imhotep debris fields ice grains [3]; 3) different combinations of water ice and dark terrain in intimate mixing with small grains (tens of microns) or in areal mixing with large grains (mm- sized) are seen on the eight bright areas discussed in [4]; 4) the CO2 ice in the Anhur region appears grouped in areal patches made of 50 μm sized grains [5]. While the spectroscopic identification of water and carbon dioxide ices is made by means of diagnostic infrared absorption features, their presence cause significant effects also at visible wavelengths, including the increase of the albedo and the reduction of the spectral slope which results in a more blue color [9,10]. In summary, thermodynamic conditions prevailing on the 67P/CG nucleus surface allow the presence of only H2O and CO2 ices. Similar properties are probably common among other Jupiter family comets.

Item URL in elib:https://elib.dlr.de/115423/
Document Type:Conference or Workshop Item (Speech)
Title:Water and carbon dioxide ices-rich areas on comet 67P/CG nucleus surface
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Filacchione, G.inaf-iasf, rome, italyUNSPECIFIED
Capaccioni, F.inaf-iasf, italyUNSPECIFIED
Raponi, A.inaf-iasf, italyUNSPECIFIED
Desanctis, M.C.inaf, istituto di astrofisica spaziale e fisica cosmica, roma, italyUNSPECIFIED
Ciarniello, M.inaf-iasf, italyUNSPECIFIED
Barucci, M. A.observatoire de paris, meudon, franceUNSPECIFIED
Tosi, F.inaf-iasf istituto di astrofisica spaziale e fisica cosmica, roma italyUNSPECIFIED
Migliorini, A.inaf-iasfUNSPECIFIED
Capria, M. T.instituto di astrofisica spaziale e fisica cosmica, roma, italyUNSPECIFIED
Erard, S.lesiaUNSPECIFIED
Bockelee-Morvan, D.observatoire de paris, meudonUNSPECIFIED
Leyrat, C.lesiaUNSPECIFIED
Arnold, GabrieleGabriele.Arnold (at) dlr.deUNSPECIFIED
Kappel, Daviddavid.kappel (at) dlr.deUNSPECIFIED
McCord, Thomas B.bear fight institute, winthrop, wa, united states.UNSPECIFIED
Date:23 January 2017
Journal or Publication Title:Ices in the Solar System
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Page Range:pp. 1-2
Status:Published
Keywords:VIRTIS, comets, Rosetta, 67P, water ice, carbon dioxide ice
Event Title:Ices in the Solar System
Event Location:Madrid, Spain
Event Type:international Conference
Event Dates:23-26 January 2017
Organizer:ESA
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Space Science and Exploration
DLR - Research area:Raumfahrt
DLR - Program:R EW - Erforschung des Weltraums
DLR - Research theme (Project):R - Projekt ROSETTA Instrumente
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 15:41
Last Modified:31 Jul 2019 20:12

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