Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko

Nicholas Thomas 1 B. Davidsson 2 Mohamed Ramy El-Maarry 1 Sonia Fornasier 3, 4 L. Giacomini 5 A.G. Gracia Berna 1 S.F. Hviid 6 W.-H. Ip 7 Laurent Jorda 8 H.U. Keller 9 J. Knollenberg 6 E. Kührt 6 F. La Forgia 10 I.L. Lai 7 Y. Liao R. Marschall 1 Matteo Massironi 5 S. Mottola 6 Maurizio Pajola 11 O. Poch 1 A. Pommerol 1 Frank Preusker 6 Frank Scholten 6 C.C. Su 12 J.S. Wu 12 J.-B. Vincent 13 Holger Sierks 13 C. Barbieri 10 P.L. Lamy 8 R. Rodrigo 14, 15 D. Koschny 16 H. Rickman 2 M. F. A’hearn 17 M. Antonella Barucci 4 Jean-Loup Bertaux 18 Ivano Bertini 11 Gabriele Cremonese 19 V. Da Deppo 20 S. Debei 21 M. De Cecco 22 Marco Fulle 23 O. Groussin 8 Pedro J. Gutierrez 24 J.-R. Kramm 13 Michael Küppers 25 L. M. Lara 24 M. Lazzarin 10 J. J. Lopez Moreno 24 Francesco Marzari 10 Harald Michalik 26 Giampiero Naletto 11, 21, 20 Jessica Agarwal 13 C. Güttler 13 N. Oklay 13 Cecilia Tubiana 13
Abstract : 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 nu- cleus 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.
Type de document :
Article dans une revue
Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 583, A17 (18 p.). <10.1051/0004-6361/201526049>
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Soumis le : dimanche 20 septembre 2015 - 18:08:17
Dernière modification le : lundi 29 mai 2017 - 15:03:45

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Nicholas Thomas, B. Davidsson, Mohamed Ramy El-Maarry, Sonia Fornasier, L. Giacomini, et al.. Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko. Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 583, A17 (18 p.). <10.1051/0004-6361/201526049>. <insu-01202385>

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