Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko
Thomas, N. and Davidsson, B. and El-Maarry, Mohamed Ramy and Fornasier, S. and Giacomini, L. and Gracia-Berná, A.G. and Hviid, S.F. and Ip, W.-H. and Jorda, L. and Keller, H.U. and Knollenberg, J. and Kührt, E. and La Forgia, F. and Lai, I.L. and Liao, Y. and Marschall, R. and Massironi, M. and Mottola, S. and Pajola, M. and Poch, O. and Pommerol, A. and Preusker, F. and Scholten, F. and Su, C.C. and Wu, J.S. and Vincent, J.-B. and Sierks, H. and Barbieri, C. and Lamy, P.L. and Rodrigo, R. and Koschny, D. and Rickman, H. and A’Hearn, M.F. and Barucci, M.A. and Bertaux, J.-L. and Bertini, I. and Cremonese, G. and Da Deppo, V. and Debei, S. and de Cecco, M. and Fulle, M. and Groussin, O. and Gutierrez, P.J. and Kramm, J.-R. and Küppers, M. and Lara, L.M. and Lazzarin, M. and Lopez Moreno, J. J. and Marzari, F. and Michalik, H. and Naletto, G. and Agarwal, J. and Güttler, C. and Oklay, N. and Tubiana, C. (2015) Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko. Astronomy & Astrophysics 583 , A17. ISSN 0004-6361.
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.
Metadata
| Item Type: | Article |
|---|---|
| Keyword(s) / Subject(s): | space vehicles: instruments / comets: individual: 67P/Churyumov-Gerasimenko / techniques: image processing / hydrodynamics |
| School: | Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences |
| Depositing User: | Administrator |
| Date Deposited: | 20 Nov 2018 14:11 |
| Last Modified: | 20 Nov 2018 14:11 |
| URI: | http://eprints.bbk.ac.uk/id/eprint/25199 |
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