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Seasonal temperature effects on comet 67P/Churyumov-Gerasimenko as inferred from Rosetta/VIRTIS

Tosi, F. and Capaccioni, F. and Filacchione, G. and Leyrat, C. and Raponi, A. and Arnold, Gabriele and Capria, M. T. and De Sanctis, M.C. and Erard, S. and Piccioni, G. and Schmitt, B. and Bockelee-Morvan, D. and Combe, J.-P. and Formisano, M. and Kührt, E. and Longobardo, A and Mottola, S. and Palomba, E. (2015) Seasonal temperature effects on comet 67P/Churyumov-Gerasimenko as inferred from Rosetta/VIRTIS. In: 10th European Planetary Science Congress (EPSC), 10, p. 268. European Planetary Science Congress 2015, 27 Sep - 02 Oct 2015, Nantes, France.

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Official URL: http://meetingorganizer.copernicus.org/EPSC2015/EPSC2015-268.pdf

Abstract

The Visible InfraRed Thermal Imaging Spectrometer (VIRTIS) on board the orbiter of the ESA Rosetta mission operates in the spectral range 0.25-5.1 μm. VIRTIS is continually used to map and investigate the surface composition of the comet nucleus in its uppermost layer within a depth of a few tens of microns. Moreover, the temperature of these surface layers can be mapped utilizing VIRTIS’ long wavelength spectral measurements. To do this, the VIRTIS team uses a Bayesian approach to nonlinear inversion, which was already adopted in the past for other small bodies. The superficial layer sampled by VIRTIS is significantly different from the much thicker layers sampled by the Microwave Instrument for the Rosetta Orbiter (MIRO). Furthermore, VIRTIS is not sensitive to physical temperatures on the nightside of the comet, where the signal is considerably low. Typically, 170 K is the minimum surface temperature that can be measured while preserving small formal errors (<1 K on retrieved temperatures). Temperatures below ~170 K have increasingly lower accuracy, and should be carefully interpreted. In previous papers, we have provided a thorough description of surface temperature maps and thermal properties of comet 67P/Churyumov-Gerasimenko as derived from infrared data acquired by Rosetta/VIRTIS in the early Mapping phase carried out in August and September 2014. We divided those maps into intervals of true local solar time and we evaluated, for the available coverage, the average daily temperatures. In addition, we studied correlations between temperature and albedo at different wavelengths, and derived diurnal temperature profiles for several local sites, representative of as many macro-regions of the comet. In this new work, we focus on effects determined by the season and the heliocentric distance. Due to the low thermal inertia of the nucleus surface material, the surface temperature is essentially dominated by the instantaneous value of the solar incidence angle. Small values of this angle result in high surface temperatures, but, due to comet 67P’s obliquity, for each location the smallest achievable value of insolation angle depends on the season. During 2014, VIRTIS’ visible and infrared measurements covered only the northern regions of the cometary surface and the equatorial belt became gradually unveiled, while the southern region is going to be revealed from 2015 onwards.

Item URL in elib:https://elib.dlr.de/100891/
Document Type:Conference or Workshop Item (Poster)
Title:Seasonal temperature effects on comet 67P/Churyumov-Gerasimenko as inferred from Rosetta/VIRTIS
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Tosi, F.INAF-IASF Istituto di Astrofisica Spaziale e Fisica Cosmica, Roma ItalyUNSPECIFIED
Capaccioni, F.INAF-IASF, italyUNSPECIFIED
Filacchione, G.INAF-IASF, Rome, ItalyUNSPECIFIED
Leyrat, C.LESIAUNSPECIFIED
Raponi, A.INAF-IASF, ItalyUNSPECIFIED
Arnold, GabrieleGabriele.Arnold (at) dlr.deUNSPECIFIED
Capria, M. T.Instituto di Astrofisica Spaziale e Fisica Cosmica, Roma, ItalyUNSPECIFIED
De Sanctis, M.C.Istituto Nazionale di Astrofisica, Rome, Italy.UNSPECIFIED
Erard, S.LESIAUNSPECIFIED
Piccioni, G.INAF-IASFUNSPECIFIED
Schmitt, B.Grenoble Planetology LaboratoryUNSPECIFIED
Bockelee-Morvan, D.Observatoire de Paris, MeudonUNSPECIFIED
Combe, J.-P.Bear Fight Institute, 22 Fiddler’s Road, Box 667, Winthrop, Washington 98862, USAUNSPECIFIED
Formisano, M.INAF-IAPS Istituto di Astrofisica e Planetologia Spaziali, Rome, ItalyUNSPECIFIED
Kührt, E.ekkehard.kuehrt (at) dlr.deUNSPECIFIED
Longobardo, AINAF-LAPS, Via del Fosso del Cavaliere 100, I-00133 Rome, ItalyUNSPECIFIED
Mottola, S.stefano.mottola (at) dlr.deUNSPECIFIED
Palomba, E.Institute for Interplanetary Space Physics - INAF, Rome, ItalyUNSPECIFIED
Date:29 September 2015
Journal or Publication Title:10th European Planetary Science Congress (EPSC)
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Volume:10
Page Range:p. 268
Series Name:EPSC Abstracts
Status:Published
Keywords:VIRTIS, Rosetta, 67P, temperature
Event Title:European Planetary Science Congress 2015
Event Location:Nantes, France
Event Type:international Conference
Event Dates:27 Sep - 02 Oct 2015
Organizer:Europlanet
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 > Leitungsbereich PF
Institute of Planetary Research > Asteroids and Comets
Deposited By: Kappel, David
Deposited On:17 Dec 2015 08:24
Last Modified:31 Jul 2019 19:58

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