Dark side of comet 67P/Churyumov-Gerasimenko in Aug.-Oct. 2014: MIRO/Rosetta continuum observations of polar night in the southern regions

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/101642

Title:	Dark side of comet 67P/Churyumov-Gerasimenko in Aug.-Oct. 2014: MIRO/Rosetta continuum observations of polar night in the southern regions
Authors:	葉永烜;Choukroun, M.;Keihm, S.;Schloerb, F. P.;Gulkis, S.;Lellouch, E.;Leyrat, C.;von Allmen, P.;Biver, N.;Bockelée-Morvan, D.;Crovisier, J.;Encrenaz, P.;Hartogh, P.;Hofstadter, M.;Ip, W.-H.;Jarchow, C.;Janssen, M.;Lee, S.;Rezac, L.;Beaudin, G.;Gaskell, B.;Jorda, L.;Keller, H. U.;Sierks, H.
Contributors:	理學院天文研究所
Keywords:	Astrophysics;Channels;Comets;Continuums;Mathematical models;Night;Nuclei;Polar regions;Sciences of the Universe;Specific heat
Date:	2015-11-01
Issue Date:	2026-04-21 14:39:49 (UTC+8)
Publisher:	EDP Sciences
Abstract:	摘要： The high obliquity (~50[degrees]) of comet 67P/Churyumov-Gerasimenko (67P) is responsible for a long-lasting winter polar night in the southern regions of the nucleus. We report observations made with the submillimeter and millimeter continuum channels of the Microwave Instrument onboard the Rosetta Orbiter (MIRO) of the thermal emission from these regions during the period August-October 2014. Before these observations, the southern polar regions had been in darkness for approximately five years. Subsurface temperatures in the range 25-50 K are measured. Thermal model calculations of the nucleus near-surface temperatures carried out over the orbit of 67P, coupled with radiative transfer calculations of the MIRO channels brightness temperatures, suggest that these regions have a thermal inertia within the range 10-60 J m super(-2) K super(-1) s super(-0.5). Such low thermal inertia values are consistent with a highly porous, loose, regolith-like surface. These values are similar to those derived elsewhere on the nucleus. A large difference in the brightness temperatures measured by the two MIRO continuum channels is tentatively attributed to dielectric properties that differ significantly from the sunlit side, within the first few tens of centimeters. This is suggestive of the presence of ice(s) within the MIRO depths of investigation in the southern polar regions. These regions started to receive sunlight in May of 2015, and refinements of the shape model in these regions, as well as continuing MIRO observations of 67P, will allow refining these results and reveal the thermal properties and potential ice content of the southern regions in more detail. 出版者： EDP Sciences 出版日期： 2015-11 出處： Astronomy and astrophysics (Berlin), 2015-11, Vol.583, p.A28 資源來源： EDP Sciences 版權： licence_http://creativecommons.org/publicdomain/zero 識別號： ISSN: 0004-6361 識別號： EISSN: 1432-0746 識別號： DOI: 10.1051/0004-6361/201526181
Appears in Collections:	[Graduate Institute of Astronomy] journal & Dissertation

Files in This Item:

File	Description	Size	Format
index.html		0Kb	HTML	16	View/Open

社群 sharing

Loading...