Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko
Journal
Date Issued
2015
Author(s)
Thomas, N.
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Davidsson, B.
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El-Maarry, M. R.
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Fornasier, S.
•
•
Gracia-Berná, A. G.
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Hviid, S. F.
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Ip, W. -H.
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Jorda, L.
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Keller, H. U.
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Knollenberg, J.
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Kührt, E.
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La Forgia, F.
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Lai, I. L.
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Liao, Y.
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Marschall, R.
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Massironi, M.
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Mottola, S.
•
•
Poch, O.
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Pommerol, A.
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Preusker, F.
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Scholten, F.
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Su, C. C.
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Wu, J. S.
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Vincent, J. -B.
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Sierks, H.
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Barbieri, C.
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Lamy, P. L.
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Rodrigo, R.
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Koschny, D.
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Rickman, H.
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A'Hearn, M. F.
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Barucci, M. A.
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Bertaux, J. -L.
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Bertini, I.
•
•
Da Deppo, V.
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Debei, S.
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de Cecco, M.
•
•
Groussin, O.
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Gutierrez, P. J.
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Kramm, J. -R.
•
Küppers, M.
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Lara, L. M.
•
Lazzarin, M.
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Lopez Moreno, J. J.
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Marzari, F.
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Michalik, H.
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Naletto, G.
•
Agarwal, J.
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Güttler, C.
•
Oklay, N.
•
Description
OSIRIS was built by a consortium of the Max-Planck-Institut für Sonnensystemforschung, in Göttingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d’Astrophysique de Marseille, France, the Instituto de Astrofisica de Andalucia, CSIC, Granada, Spain, the Research and Scientific Support Department of the European Space Agency, Noordwijk, The Netherlands, the Instituto Nacional de Tecnica Aeroespacial, Madrid, Spain, the Universidad Politechnica de Madrid, Spain, the Department of Physics and Astronomy of Uppsala University, Sweden, and the Institut für Datentechnik und Kommunikationsnetze der Technischen Universität Braunschweig, Germany. 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. The team from the University of Bern is supported through the Swiss National Science Foundation (grant No. ) and through NCCR PlanetS.
Abstract
Context. We present an investigation of the surface properties of areas on the nucleus of comet 67P/Churyumov-Gerasimenko.
Aims: We aim to show that transport of material from one part of the cometary nucleus to another is a significant mechanism that influences the appearance of the nucleus and the surface thermal properties.
Methods: We used data from the OSIRIS imaging system onboard the Rosetta spacecraft to identify surface features on the nucleus that can be produced by various transport mechanisms. We used simple calculations based on previous works to establish the plausibility of dust transport from one part of the nucleus to another.
Results: We show by observation and modeling that "airfall" as a consequence of non-escaping large particles emitted from the neck region of the nucleus is a plausible explanation for the smooth thin deposits in the northern hemisphere of the nucleus. The consequences are also discussed. We also present observations of aeolian ripples and ventifacts. We show by numerical modeling that a type of saltation is plausible even under the rarified gas densities seen at the surface of the nucleus. However, interparticle cohesive forces present difficulties for this model, and an alternative mechanism for the initiation of reptation and creep may result from the airfall mechanism. The requirements on gas density and other parameters of this alternative make it a more attractive explanation for the observations. The uncertainties and implications are discussed.
Aims: We aim to show that transport of material from one part of the cometary nucleus to another is a significant mechanism that influences the appearance of the nucleus and the surface thermal properties.
Methods: We used data from the OSIRIS imaging system onboard the Rosetta spacecraft to identify surface features on the nucleus that can be produced by various transport mechanisms. We used simple calculations based on previous works to establish the plausibility of dust transport from one part of the nucleus to another.
Results: We show by observation and modeling that "airfall" as a consequence of non-escaping large particles emitted from the neck region of the nucleus is a plausible explanation for the smooth thin deposits in the northern hemisphere of the nucleus. The consequences are also discussed. We also present observations of aeolian ripples and ventifacts. We show by numerical modeling that a type of saltation is plausible even under the rarified gas densities seen at the surface of the nucleus. However, interparticle cohesive forces present difficulties for this model, and an alternative mechanism for the initiation of reptation and creep may result from the airfall mechanism. The requirements on gas density and other parameters of this alternative make it a more attractive explanation for the observations. The uncertainties and implications are discussed.
Volume
583
Start page
A17
Issn Identifier
0004-6361
Ads BibCode
2015A&A...583A..17T
Rights
open.access
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