Are fractured cliffs the source of cometary dust jets ? insights from OSIRIS/Rosetta at 67P/Churyumov-Gerasimenko

Jean-Baptiste Vincent 1 Nilda Oklay 1 Maurizio Pajola 2 Sebastien Höfner 1, 3 Holger Sierks 1 X. Hu 1, 3 Cesare Barbieri 4 Philippe L. Lamy 5 R. Rodrigo 6, 7 Detlef Koschny 8 Hans Rickman 9, 10 Horst Uwe Keller 3 Michael F. A'Hearn 11, 1, 12 Maria A. Barucci 13 Jean-Loup Bertaux 14 I. Bertini 2 S. Besse 8 D. Bodewits 12 Gabriele Cremonese 15 Vania Da Deppo 16 B. Davidsson 10 Stefano Debei 17 M. De Cecco 18 Mohamed R. El-Maarry 19 Sonia Fornasier 13 M. Fulle 20 Olivier Groussin 5 P. J. Gutiérrez 21 P. Gutiérrez-Marquez 1 C. Güttler 1 M. Hofmann 1 S. F. Hviid 22 W. -H. Ip 23 L. Jorda 5 J. Knollenberg 22 G. Kovacs 1, 24 J. -R. Kramm 1 E. Kührt 22 M. Küppers 25 L. M. Lara 21 M. Lazzarin 4 Z. -Y. Lin 23 J. J. Lopez Moreno 21 S. Lowry 26 F. Marzari 4 M. Massironi 2 F. Moreno 21 S. Mottola 22 G. Naletto 2, 16, 27 F. Preusker 22 F. Scholten 22 X. Shi 1 Nicholas Thomas 19 I. Toth 28, 5 C. Tubiana 1
Abstract : Dust jets (i.e., fuzzy collimated streams of cometary material arising from the nucleus) have been observed in situ on all comets since the Giotto mission flew by comet 1P/Halley in 1986, and yet their formation mechanism remains unknown. Several solutions have been proposed involving either specific properties of the active areas or the local topography to create and focus the gas and dust flows. While the nucleus morphology seems to be responsible for the larger features, high resolution imagery has shown that broad streams are composed of many smaller jets (a few meters wide) that connect directly to the nucleus surface. Aims. We monitored these jets at high resolution and over several months to understand what the physical processes are that drive their formation and how this affects the surface. Methods. Using many images of the same areas with different viewing angles, we performed a 3-dimensional reconstruction of collimated jets and linked them precisely to their sources on the nucleus. Results. We show here observational evidence that the northern hemisphere jets of comet 67P/Churyumov-Gerasimenko arise from areas with sharp topographic changes and describe the physical processes involved. We propose a model in which active cliffs are the main source of jet-like features and therefore of the regions eroding the fastest on comets. We suggest that this is a common mechanism taking place on all comets.
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Soumis le : lundi 15 février 2016 - 17:12:18
Dernière modification le : mardi 30 mai 2017 - 01:19:30



Jean-Baptiste Vincent, Nilda Oklay, Maurizio Pajola, Sebastien Höfner, Holger Sierks, et al.. Are fractured cliffs the source of cometary dust jets ? insights from OSIRIS/Rosetta at 67P/Churyumov-Gerasimenko. Astronomy and Astrophysics - A&A, EDP Sciences, 2016, 587 (March), A14 (15 p.). <10.1051/0004-6361/201527159>. <insu-01274339>



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