Si-BEARING MOLECULES TOWARD IRC+10216: ALMA UNVEILS THE MOLECULAR ENVELOPE OF CWLeo
ABSTRACT We report the detection of SiS rotational lines in high-vibrational states as well as SiO and SiC2 lines in their ground vibrational state toward IRC+10216 during the Atacama Large Millimeter Array Cycle 0. The spatial distribution of these molecules shows compact emission for SiS and a mor...
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Published in | Astrophysical journal. Letters Vol. 805; no. 2; pp. 1 - 7 |
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Main Authors | , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
The American Astronomical Society
01.06.2015
Bristol : IOP Publishing |
Subjects | |
Online Access | Get full text |
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Summary: | ABSTRACT We report the detection of SiS rotational lines in high-vibrational states as well as SiO and SiC2 lines in their ground vibrational state toward IRC+10216 during the Atacama Large Millimeter Array Cycle 0. The spatial distribution of these molecules shows compact emission for SiS and a more extended emission for SiO and SiC2 and also proves the existence of an increase in the SiC2 emission at the outer shells of the circumstellar envelope (CSE). We analyze the excitation conditions of the vibrationally excited SiS using the population diagram technique, and we use a large velocity gradient model to compare with the observations. We found moderate discrepancies between the observations and the models that could be explained if SiS lines detected are optically thick. Additionally, the line profiles of the detected rotational lines in the high-energy vibrational states show a decreasing linewidth with increasing energy levels. This may be evidence that these lines could be excited only in the inner shells, i.e., the densest and hottest, of the CSE of IRC+10216. |
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Bibliography: | LET32750 ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 PMCID: PMC4681092 |
ISSN: | 2041-8205 2041-8213 2041-8213 |
DOI: | 10.1088/2041-8205/805/2/L13 |