@article{d6adaf2f437646c08e178760a5e934db,
title = "Redistribution of particles across the nucleus of comet 67P/Churyumov-Gerasimenko",
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.",
keywords = "Comets: individual: 67P/Churyumov-Gerasimenko, Hydrodynamics, Space vehicles: instruments, Techniques: image processing",
author = "N. Thomas and B. Davidsson and El-Maarry, \{M. R.\} and S. Fornasier and L. Giacomini and Gracia-Bern{\'a}, \{A. G.\} and Hviid, \{S. F.\} and Ip, \{W. H.\} and L. Jorda and Keller, \{H. U.\} and J. Knollenberg and E. K{\"u}hrt and \{La Forgia\}, F. and Lai, \{I. L.\} and Y. Liao and R. Marschall and M. Massironi and S. Mottola and M. Pajola and O. Poch and A. Pommerol and F. Preusker and F. Scholten and Su, \{C. C.\} and Wu, \{J. S.\} and Vincent, \{J. B.\} and H. Sierks and C. Barbieri and Lamy, \{P. L.\} and R. Rodrigo and D. Koschny and H. Rickman and A'Hearn, \{M. F.\} and Barucci, \{M. A.\} and Bertaux, \{J. L.\} and I. Bertini and G. Cremonese and \{Da Deppo\}, V. and S. Debei and \{De Cecco\}, M. and M. Fulle and O. Groussin and Gutierrez, \{P. J.\} and Kramm, \{J. R.\} and M. K{\"u}ppers and Lara, \{L. M.\} and M. Lazzarin and \{Lopez Moreno\}, \{J. J.\} and F. Marzari and H. Michalik and G. Naletto and J. Agarwal and C. G{\"u}ttler and N. Oklay and C. Tubiana",
note = "Funding Information: OSIRIS was built by a consortium of the Max-Planck-Institut f{\"u}r Sonnensystemforschung, in G{\"o}ttingen, Germany, CISAS-University of Padova, Italy, the Laboratoire d{\textquoteright}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 f{\"u}r Datentechnik und Kommunikationsnetze der Technischen Universit{\"a}t 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. Publisher Copyright: {\textcopyright} 2015 ESO.",
year = "2015",
month = nov,
day = "1",
doi = "10.1051/0004-6361/201526049",
language = "British English",
volume = "583",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
}