Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS

M.R. El-Maarry 1 N. Thomas 1 A. Gracia-Berná 1 R. Marschall 1 A-T. Auger 2 O. Groussin 2 S. Mottola 3 M. Pajola 4 M. Massironi 4, 5 S. Marchi 6 S. Höfner 7 F. Preusker 3 F. Scholten 3 L. Jorda 2 E. Kührt 3 H. U. Keller 3, 8 H. Sierks 7 M. F. A'Hearn 9 C. Barbieri 10 M. A. Barucci 11 Jean-Loup Bertaux 12 I. Bertini 4 G. Cremonese 13 V. Da Deppo 14 B. Davidsson 15 S. Debei 16 M. De Cecco 17 J. Deller 7 C. Güttler 7 S. Fornasier 11 M. Fulle 18 P. J. Gutierrez 19 M. Hofmann 7 S. F. Hviid 3 W-H. Ip 20 J. Knollenberg 3 D. Koschny 21 G. Kovacs 7 J.-R. Kramm 7 M. Küppers 22 P. L. Lamy 2 L. M. Lara 19 M. Lazzarin 10 J. J. Lopez Moreno 19 F. Marzari 10 H. Michalik 23 G. Naletto 4, 14, 16 N. Oklay 7 A. Pommerol 1 H. Rickman 15, 24 R. Rodrigo 25, 26 C. Tubiana 7 J-B. Vincent 7
Abstract : The OSIRIS experiment onboard the Rosetta spacecraft currently orbiting comet 67P/Churyumov-Gerasimenko has yielded unprecedented views of a comet's nucleus. We present here the first ever observations of meter-scale fractures on the surface of a comet. Some of these fractures form polygonal networks. We present an initial assessment of their morphology, topology, and regional distribution. Fractures are ubiquitous on the surface of the comet's nucleus. Furthermore, they occur in various settings and show different topologies suggesting numerous formation mechanisms, which include thermal insolation weathering, orbital-induced stresses, and possibly seasonal thermal contraction. However, we conclude that thermal insolation weathering is responsible for creating most of the observed fractures based on their morphology and setting in addition to thermal models that indicate diurnal temperature ranges exceeding 200 K and thermal gradients of ~15 K/min at perihelion are possible. Finally, we suggest that fractures could be a facilitator in surface evolution and long-term erosion.
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Article dans une revue
Geophysical Research Letters, American Geophysical Union, 2015, 42 (13), pp.5170-5178. 〈10.1002/2015GL064500〉
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Soumis le : mardi 14 juillet 2015 - 14:52:43
Dernière modification le : jeudi 9 novembre 2017 - 09:36:02

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M.R. El-Maarry, N. Thomas, A. Gracia-Berná, R. Marschall, A-T. Auger, et al.. Fractures on comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS. Geophysical Research Letters, American Geophysical Union, 2015, 42 (13), pp.5170-5178. 〈10.1002/2015GL064500〉. 〈insu-01176074〉

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