SiS in the Circumstellar Envelope of IRC+10216: Maser and Quasi-thermal Emission | |
Gong, Y.1,2,3; Henkel, C.3,4; Ott, J.5; Menten, K. M.3; Morris, M. R.6; Keller, D.3,7; Claussen, M. J.5; Grasshoff, M.3; Mao, R. Q.1,2 | |
刊名 | ASTROPHYSICAL JOURNAL |
2017-07-01 | |
卷号 | 843期号:1页码:18 |
关键词 | masers radio lines: stars stars: AGB and post-AGB stars: carbon stars: individual (IRC+10216) |
ISSN号 | 0004-637X |
DOI | 10.3847/1538-4357/aa7853 |
英文摘要 | We present new Effelsberg 100-m, Australia Telescope Compact Array (ATCA), and Very Large Array observations of rotational SiS transitions in the circumstellar envelope (CSE) of IRC +10216. Thanks to the high angular resolution achieved by the ATCA observations, we unambiguously confirm that the molecule's J= 1 (R) 0 transition exhibits maser action in this CSE, as first suggested more than 30 years ago. The maser emission's radial velocity, peaking at a local standard of rest velocity of -39.862 +/- 0.065 km s-1, indicates that it arises from an almost fully accelerated shell. Monitoring observations show time variability of the SiS (1 (R) 0) maser. The two lowest-J SiS quasi-thermal emission lines trace a much more extended emitting region than previous high-J SiS observations. Their distributions show that the SiS quasi-thermal emission consists of two components: one is very compact (radius < 1."5, corresponding to <3 x 10(15) cm), and the other extends out to a radius >11''. An incomplete shell-like structure is found in the northeast, which is indicative of existing SiS shells. Clumpy structures are also revealed in this CSE. The gain of the SiS (1 (R) 0) maser (optical depths of about -5 at the blueshifted side and, assuming inversion throughout the entire line's velocity range, about -2 at the redshifted side) suggests that it is unsaturated. The SiS (1 (R) 0) maser can be explained in terms of ro-vibrational excitation caused by infrared pumping, and we propose that infrared continuum emission is the main pumping source. |
WOS关键词 | CARBON STAR IRC+10216 ; SUBMILLIMETER HCN LASER ; MOLECULAR ENVELOPE ; EVOLVED STARS ; LINE SURVEY ; DUST SHELL ; EXPANDING ENVELOPES ; INNER LAYERS ; CW LEONIS ; MU-M |
WOS研究方向 | Astronomy & Astrophysics |
语种 | 英语 |
出版者 | IOP PUBLISHING LTD |
WOS记录号 | WOS:000404605200018 |
内容类型 | 期刊论文 |
源URL | [http://libir.pmo.ac.cn/handle/332002/22955] |
专题 | 中国科学院紫金山天文台 |
通讯作者 | Gong, Y. |
作者单位 | 1.Chinese Acad Sci, Purple Mt Observ, 2 West Beijing Rd, Nanjing 210008, Jiangsu, Peoples R China 2.Chinese Acad Sci, Key Lab Radio Astron, 2 West Beijing Rd, Nanjing 210008, Jiangsu, Peoples R China 3.Max Planck Inst Radioastron, Hugel 69, D-53121 Bonn, Germany 4.King Abdulaziz Univ, Dept Astron, POB 80203, Jeddah 21589, Saudi Arabia 5.Natl Radio Astron Observ, POB O,1003 Lopezville Rd, Socorro, NM 87801 USA 6.Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA 7.Katholieke Univ Leuven, Inst Sterrenkunde, Celestijnenlaan 200D, B-3001 Leuven, Belgium |
推荐引用方式 GB/T 7714 | Gong, Y.,Henkel, C.,Ott, J.,et al. SiS in the Circumstellar Envelope of IRC+10216: Maser and Quasi-thermal Emission[J]. ASTROPHYSICAL JOURNAL,2017,843(1):18. |
APA | Gong, Y..,Henkel, C..,Ott, J..,Menten, K. M..,Morris, M. R..,...&Mao, R. Q..(2017).SiS in the Circumstellar Envelope of IRC+10216: Maser and Quasi-thermal Emission.ASTROPHYSICAL JOURNAL,843(1),18. |
MLA | Gong, Y.,et al."SiS in the Circumstellar Envelope of IRC+10216: Maser and Quasi-thermal Emission".ASTROPHYSICAL JOURNAL 843.1(2017):18. |
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