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Electrical Properties and Porosity of the First Meter of the Nucleus of 67P/Churyumov-Gerasimenko

Lethuillier, Anthony and Le Gall, Alice and Hamelin, Michel and Schmidt, Walter and Seidensticker, Klaus J. and Grard, R. and Ciarletti, V. and Caujolle-Bert, Sylvain and Fischer, Hans-Herbert and Trautner, Roland (2016) Electrical Properties and Porosity of the First Meter of the Nucleus of 67P/Churyumov-Gerasimenko. Astronomy & Astrophysics, 591, A32/1-A32/17. EDP Sciences. DOI: 10.1051/0004-6361/201628304 ISSN 0004-6361

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Abstract

Context. Comets are primitive objects, remnants of the volatile-rich planetesimals from which the solar system condensed. Knowing their structure and composition is thus crucial for the understanding of our origins. After the successful landing of Philae on the nucleus of 67P/Churyumov-Gerasimenko in November 2014, for the first time, the Rosetta mission provided the opportunity to measure the low frequency electrical properties of a cometary mantle with the permittivity probe SESAME-PP (Surface Electric Sounding and Acoustic Monitoring Experiment−Permittivity Probe). Aims. In this paper, we conduct an in-depth analysis of the data from active measurements collected by SESAME-PP at Abydos, which is the final landing site of Philae, to constrain the porosity and, to a lesser extent, the composition of the surface material down to a depth of about 1 m. Methods. SESAME-PP observations on the surface are then analyzed by comparison with data acquired during the descent toward the nucleus and with numerical simulations that explore different possible attitudes and environments of Philae at Abydos using a method called the Capacity-Influence Matrix Method. Results. Reasonably assuming that the two receiving electrode channels have not drifted with respect to each other during the ten-year journey of the Rosetta probe to the comet, we constrain the dielectric constant of the first meter below the surface at Abydos to be >2.45 ± 0.20, which is consistent with a porosity <50% if the dust phase is analogous to carbonaceous chondrites and <75% in the case of less primitive ordinary chondrites. This indicates that the near surface of the nucleus of 67P/Churyumov-Gerasimenko is more compacted than its interior and suggests that it could consist of a sintered dust-ice layer.

Item URL in elib:https://elib.dlr.de/109307/
Document Type:Article
Title:Electrical Properties and Porosity of the First Meter of the Nucleus of 67P/Churyumov-Gerasimenko
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Lethuillier, Anthonylatmos, paris, frankreichUNSPECIFIED
Le Gall, Alicelatmos, paris, frankreichUNSPECIFIED
Hamelin, Michellatmos, paris, frankreichUNSPECIFIED
Schmidt, Walterfmi, helsinki, finnlandUNSPECIFIED
Seidensticker, Klaus J.Klaus.Seidensticker (at) dlr.dehttps://orcid.org/0000-0003-3671-3769
Grard, R.ESA, estec, NiederlandeUNSPECIFIED
Ciarletti, V.latmos, Paris,FrankreichUNSPECIFIED
Caujolle-Bert, Sylvainlatmos, paris, frankreichUNSPECIFIED
Fischer, Hans-HerbertHans-Herbert.Fischer (at) dlr.deUNSPECIFIED
Trautner, RolandESA, estec, niederlandeUNSPECIFIED
Date:2016
Journal or Publication Title:Astronomy & Astrophysics
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:591
DOI :10.1051/0004-6361/201628304
Page Range:A32/1-A32/17
Publisher:EDP Sciences
ISSN:0004-6361
Status:Published
Keywords:Rosetta Philae SESAME PP Comets: individual: 67P/Churyumov-Gerasimenko Methods: numerical Methods: data analysis Space vehicles: instruments Planets and satellites: surfaces
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 , Köln-Porz
Institutes and Institutions:Institute of Planetary Research
Space Operations and Astronaut Training > User center for space experiments (MUSC)
Deposited By: Seidensticker, Dr. Klaus J.
Deposited On:15 Dec 2016 08:58
Last Modified:31 Jul 2019 20:06

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