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| 題名: | Large-scale dust jets in the coma of 67P/Churyumov-Gerasimenko as seen by the OSIRIS instrument onboard Rosetta |
| 作者: | 林忠義;Lara, L. M.;Lowry, S.;Vincent, J.-B.;Gutiérrez, P. J.;Rożek, A.;La Forgia, F.;Oklay, N.;Sierks, H.;Barbieri, C.;Lamy, P. L.;Rodrigo, R.;Koschny, D.;Rickman, H.;Keller, H. U.;Agarwal, J.;Auger, A.-T.;A’Hearn, M. F.;Barucci, M. A.;Bertaux, J.-L.;Bertini, I.;Besse, S.;Bodewits, D.;Cremonese, G.;Davidsson, B.;Da Deppo, V.;Debei, S.;De Cecco, M.;El-Maarry, M. R.;Ferri, F.;Fornasier, S.;Fulle, M.;Groussin, O.;Gutiérrez–Marques, P.;Güttler, C.;Hviid, S. F.;Ip, W.-H.;Jorda, L.;Knollenberg, J.;Kovacs, G.;Kramm, J.-R.;Kührt, E.;Küppers, M.;Lazzarin, M.;Lin, Z.-Y.;López-Moreno, J. J.;Magrin, S.;Marzari, F.;Michalik, H.;Moissl–Fraund, R.;Moreno, F.;Mottola, S.;Naletto, G.;Pajola, M.;Pommerol, A.;Thomas, N.;Sabau, M. D.;Tubiana, C. |
| 貢獻者: | 理學院天文研究所 |
| 關鍵詞: | Angles (geometry);Astrophysics;Comet heads;Comet nuclei;Comets;comets: general;comets: individual: 67P/Churyumov-Gerasimenko;Dust;Earth and Planetary Astrophysics;Ground-based observation;Jets;Perihelions;Sciences of the Universe |
| 日期: | 2015-11-01 |
| 上傳時間: | 2026-04-21 14:40:27 (UTC+8) |
| 出版者: | EDP Sciences |
| 摘要: | 摘要： Context. During the most recent perihelion passage in 2009 of comet 67P/Churyumov-Gerasimenko (67P), ground-based observations showed an anisotropic dust coma where jet-like features were detected at ~ 1.3 AU from the Sun. The current perihelion passage is exceptional as the Rosetta spacecraft is monitoring the nucleus activity since March 2014, when a clear dust coma was already surrounding the nucleus at 4.3 AU from the Sun. Subsequently, the OSIRIS camera also witnessed an outburst in activity between April 27 and 30, and since mid-July, the dust coma at rh ~ 3.7−3.6 AU preperihelion is clearly non-isotropic, pointing to the existence of dust jet-like features. Aims. We aim to ascertain on the nucleus surface the origin of the dust jet-like features detected as early as in mid-July 2014. This will help to establish how the localized comet nucleus activity compares with that seen in previous apparitions and will also help following its evolution as the comet approaches its perihelion, at which phase most of the jets were detected from ground-based observations. Determining these areas also allows locating them in regions on the nucleus with spectroscopic or geomorphological distinct characteristics. Methods. Three series of dust images of comet 67P obtained with the Wide Angle Camera (WAC) of the OSIRIS instrument onboard the Rosetta spacecraft were processed with different enhancement techniques. This was made to clearly show the existence of jet-like features in the dust coma, whose appearance toward the observer changed as a result of the rotation of the comet nucleus and of the changing observing geometry from the spacecraft. The position angles of these features in the coma together with information on the observing geometry, nucleus shape, and rotation, allowed us to determine the most likely locations on the nucleus surface where the jets originate from. Results. Geometrical tracing of jet sources indicates that the activity of the nucleus of 67P gave rise during July and August 2014 to large-scale jet-like features from the Hapi, Hathor, Anuket, and Aten regions, confirming that active regions may be present on the nucleus localized at 60° northern latitude as deduced from previous comet apparitions. There are also hints that large-scale jets observed from the ground are possibly composed, at their place of origin on the nucleus surface, of numerous small-scale features.
出版者： EDP Sciences
出版日期： 2015-11-01
出處： Astronomy & Astrophysics, 2015-11, Vol.583, p.A9-
資源來源： EDP Sciences
版權： CC0 1.0 - Universal
識別號： ISSN: 0004-6361
識別號： ISSN: 1432-0746
識別號： EISSN: 1432-0746
識別號： DOI: 10.1051/0004-6361/201526103 |
| 顯示於類別: | [天文研究所] 期刊論文
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