DETECTION OF A NEW INTERSTELLAR MOLECULE: THIOCYANIC ACID HSCN

Journal Article · Thu Sep 10 04:00:00 EDT 2009 · Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/702/2/L124; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21336011

Halfen, D T; Ziurys, L M ^[1]; Bruenken, S; Gottlieb, C A; McCarthy, M C

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1. Departments of Chemistry and Astronomy, Arizona Radio Observatory, and Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

A new interstellar molecule, HSCN (thiocyanic acid), an energetic isomer of the well-known species HNCS, has been detected toward Sgr B2(N) with the Arizona Radio Observatory 12 m telescope. Eight rotational transitions in the K{sub a} = 0 ladder were observed in the 2 mm and 3 mm bands. Five consecutive transitions in the 3 mm band are unblended, but three in the 2 mm band are partially masked by lines of other molecules. The peak intensity of all eight transitions are well described by a rotational temperature that is in very good agreement with that of many other molecules in this source. The line width and radial velocity of HSCN match closely with those of the ground state isomer HNCS (isothiocyanic acid), HNCO (isocyanic acid), and HOCN (cyanic acid); preliminary maps indicate that all four molecules are similarly distributed in Sgr B2. Although HSCN is calculated to lie over 3000 K higher in energy than HNCS, its column density of 1.3 x 10{sup 13} cm{sup -2} in Sgr B2(N) is only three times lower than that of HNCS. The fractional abundances of HSCN and HNCS relative to H{sub 2} are 4.5 x 10{sup -12} and 1.1 x 10{sup -11}. By analogy with the isomeric pair HCN and HNC, these two sulfur-bearing isomers are plausibly formed from a common cation precursor.

• OSTI ID: 21336011
• Journal Information: Astrophysical Journal (Online), Journal Name: Astrophysical Journal (Online) Journal Issue: 2 Vol. 702; ISSN 1538-4357
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABUNDANCE
CATIONS
GROUND STATES
HYDROGEN
ISOCYANATES
ISOMERS
LINE WIDTHS
MOLECULES
RADIAL VELOCITY
TELESCOPES
THIOCYANIC ACID