Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images

Nafiseh Masoumzadeh 1 Nilda Oklay 1 Ludmilla Kolokolova 2 Holger Sierks 1 Sonia Fornasier 3 Maria A. Barucci 3 Jean-Baptiste Vincent 1 Cécilia Tubiana 1 Carsten Güttler 1 Frank Preusker 4 Frank Scholten 4 Stefano Mottola 4 Pedro H. Hasselmann 3 Clément Feller 3 Cesare Barbieri 5 Philippe L. Lamy 6 R. Rodrigo 7, 8 D. Koschny 9 H. Rickman 10, 11 M. F. A’hearn 2, 1 Jean-Loup Bertaux 12 I. Bertini 13 G. Cremonese 14 V. Da Deppo 15 B. J. R. Davidsson 10 S. Debei 16 M. De Cecco 17 M. Fulle 18 A. Gicquel 1 O. Groussin 6 J. Gutiérrez 19 I. Hall 1 M. Hofmann 1 F. Hviid 4 W.-H. Ip 20 L. Jorda 6 H. U. Keller 21 J. Knollenberg 22 G. Kovacs 1 J.-R. Kramm 1 E. Kührt 4 M. Küppers 23 M. Lara 19 M. Lazzarin 5 J. J. Lopez Moreno 19 F. Marzari 5 G. Naletto 24, 13, 15 X. Shi 1 N. Thomas 25
Abstract : We aim to explore the behavior of the opposition effect as an important tool in optical remote sensing on the nucleus of comet 67P/ Churyumov-Gerasimenko (67P), using Rosetta-OSIRIS images acquired in different filters during the approach phase, July-August 2014 and the close flyby images on 14 of February 2015, which contain the spacecraft shadow. We based our investigation on the global and local brightness from the surface of 67P with respect to the phase angle, also known as phase curve. The local phase curve corresponds to a region that is located at the Imhotep-Ash boundary of 67P. Assuming that the region at the Imhotep-Ash boundary and the entire nucleus have similar albedo, we combined the global and local phase curves to study the opposition-surge morphology and constrain the structure and properties of 67P. The model parameters were furthermore compared with other bodies in the solar system and existing laboratory study. We found that the morphological parameters of the opposition surge decrease monotonically with wavelength, whereas in the case of coherent backscattering this behavior should be the reverse. The results from comparative analysis place 67P in the same category as the two Mars satellites, Phobos and Deimos, which are notably different from all airless bodies in the solar system. The similarity between the surface phase function of 67P and a carbon soot sample at extremely small angles is identified, introducing regolith at the boundary of the Imhotep-Ash region of 67P as a very dark and fluffy layer.
Type de document :
Article dans une revue
Astronomy and Astrophysics - A&A, EDP Sciences, 2017, 599, A11 (8 p.). <10.1051/0004-6361/201629734>
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Soumis le : mardi 21 février 2017 - 17:47:27
Dernière modification le : mardi 30 mai 2017 - 01:19:34



Nafiseh Masoumzadeh, Nilda Oklay, Ludmilla Kolokolova, Holger Sierks, Sonia Fornasier, et al.. Opposition effect on comet 67P/Churyumov-Gerasimenko using Rosetta-OSIRIS images. Astronomy and Astrophysics - A&A, EDP Sciences, 2017, 599, A11 (8 p.). <10.1051/0004-6361/201629734>. <insu-01473386>



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