Search for satellites near comet 67P/Churyumov-Gerasimenko using Rosetta/OSIRIS images

Ivano Bertini 1 Pedro J. Gutiérrez 2 Luisa M. Lara 2 Francesco Marzari 3 F. Moreno 2 Maurizio Pajola 1 Florangela La Forgia Holger Sierks 4 Cesare Barbieri 3 Philippe Lamy 5 Rafael Rodrigo 6, 7 Detlef Koschny 8 Hans Rickman 9, 10 Horst U. Keller 11 Jessica Agarwal 4 Michael F. A'Hearn 12 M.A. Barucci 13 Jean-Loup Bertaux 14 Gabriele Cremonese 15 Vania Da Deppo 16 Björn Davidsson 9 Stefano Debei 17 Mariolino De Cecco 18 Fabio Ferri 1 Sonia Fornasier 19, 13 Marco Fulle 20 Lorenza Giacomini 21 Olivier Groussin 5 Carsten Güttler 4 Stubbe F. Hviid 22 W. -H. Ip 23, 24 Laurent Jorda 5 Jörg Knollenberg 22 J.-R. Kramm 4 Ekkehard Kührt 22 Michael Küppers 25 M. Lazzarin 3 Jose J. Lopez-Moreno 2 Sara Magrin 3 Matteo Massironi 21 Harald Michalik 26 Stefano Mottola 22 Giampiero Naletto 27, 1, 16 Nilda Oklay 4 Nicholas Thomas 28 Cécilia Tubiana 4 Jean-Bapiste Vincent 4
Abstract : The European Space Agency Rosetta mission reached and started escorting its main target, the Jupiter-family comet 67P/Churyumov-Gerasimenko, at the beginning of August 2014. Within the context of solar system small bodies, satellite searches from approaching spacecraft were extensively used in the past to study the nature of the visited bodies and their collisional environ- ment. Aims. During the approaching phase to the comet in July 2014, the OSIRIS instrument onboard Rosetta performed a campaign aimed at detecting objects in the vicinity of the comet nucleus and at measuring these objects’ possible bound orbits. In addition to the scientific purpose, the search also focused on spacecraft security to avoid hazardous material in the comet’s environment. Methods. Images in the red spectral domain were acquired with the OSIRIS Narrow Angle Camera, when the spacecraft was at a distance between 5 785 km and 5 463 km to the comet, following an observational strategy tailored to maximize the scientific outcome. From the acquired images, sources were extracted and displayed to search for plausible displacements of all sources from image to image. After stars were identified, the remaining sources were thoroughly analyzed. To place constraints on the expected displacements of a potential satellite, we performed Monte Carlo simulations on the apparent motion of potential satellites within the Hill sphere. Results. We found no unambiguous detections of objects larger than ∼ 6 m within ∼ 20 km and larger than ∼ 1 m between ∼ 20 km and ∼ 110 km from the nucleus, using images with an exposure time of 0.14 s and 1.36 s, respectively. Our conclusions are consistent with independent works on dust grains in the comet coma and on boulders counting on the nucleus surface. Moreover, our analysis Article number, page 1 of 9 shows that the comet outburst detected at the end of April 2014 was not strong enough to eject large objects and to place them into a stable orbit around the nucleus. Our findings underline that it is highly unlikely that large objects survive for a long time around cometary nuclei.
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Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 583, A19 (8 p.). 〈10.1051/0004-6361/201525979〉
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Soumis le : mercredi 23 septembre 2015 - 15:24:45
Dernière modification le : jeudi 9 novembre 2017 - 09:36:02

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Ivano Bertini, Pedro J. Gutiérrez, Luisa M. Lara, Francesco Marzari, F. Moreno, et al.. Search for satellites near comet 67P/Churyumov-Gerasimenko using Rosetta/OSIRIS images. Astronomy and Astrophysics - A&A, EDP Sciences, 2015, 583, A19 (8 p.). 〈10.1051/0004-6361/201525979〉. 〈insu-01203674〉

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