SULFUR-BEARING MOLECULES IN MASSIVE STAR-FORMING REGIONS: OBSERVATIONS OF OCS, CS, H{sub 2}S, AND SO

Journal Article · Fri Mar 20 00:00:00 EDT 2015 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/802/1/40· OSTI ID:22522034

Li, Juan; Wang, Junzhi ^[1]; Zhu, Qingfeng ^[2]; Zhang, Jiangshui ^[3]; Li, Di ^[4]

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1. Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai 20030 (China)
2. Astronomy Department, University of Science and Technology, Chinese Academy of Sciences, Hefei 210008 (China)
3. Center for Astrophysics, Guangzhou University, Guangzhou 510006 (China)
4. National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100012 (China)

We studied the sulfur chemistry of massive star-forming regions through single-dish submillimeter spectroscopy. OCS, O{sup 13}CS, {sup 13}CS, H{sub 2}S, and SO transitions were observed toward a sample of massive star-forming regions with embedded UCH ii or CH ii regions. These sources could be divided into H ii-hot core and H ii-only sources based on their CH{sub 3}CN emission. Our results show that the OCS line of thirteen sources is optically thick, with optical depth ranging from 5 to 16. Column densities of these molecules were computed under LTE conditions. CS column densities were also derived using its optically thin isotopologue {sup 13}CS. H{sub 2}S is likely to be the most abundant gas-phase sulfuretted molecule in hot massive cores. Both the column density and abundance of sulfur-bearing molecules decrease significantly from H ii-hot core to H ii-only sources. Ages derived from hot core models appear to be consistent with star formation theories, suggesting that abundance ratios of [CS]/[SO], [SO]/[OCS], and [OCS]/[CS] could be used as chemical clocks in massive star-forming regions.

• OSTI ID: 22522034
• Journal Information: Astrophysical Journal, Vol. 802, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABSORPTION SPECTROSCOPY
ACETONITRILE
CARBON 13
CLOUDS
DENSITY
ELEMENT ABUNDANCE
EMISSION SPECTROSCOPY
HYDROGEN
HYDROGEN SULFIDES
LTE
MOLECULES
STAR EVOLUTION
STARS
SULFUR