Hydrogen chloride in diffuse interstellar clouds along the line of sight to W31C (G10.6-0.4)
Abstract
We report the detection of hydrogen chloride, HCl, in diffuse molecular clouds on the line of sight toward the star-forming region W31C (G10.6-0.4). The J = 1-0 lines of the two stable HCl isotopologues, H^(35)Cl and H^(37)Cl, are observed using the 1b receiver of the Heterodyne Instrument for the Far-Infrared (HIFI) on board the Herschel Space Observatory. The HCl line is detected in absorption, over a wide range of velocities associated with diffuse clouds along the line of sight to W31C. The analysis of the absorption strength yields a total HCl column density of a few 10^(13) cm^(–2), implying that HCl accounts for ~0.6% of the total gas-phase chlorine, which exceeds the theoretical model predictions by a factor of ~6. This result is comparable to those obtained from the chemically related species H_2Cl^+ and HCl^+, for which large column densities have also been reported on the same line of sight. The source of discrepancy between models and observations is still unknown; however, the detection of these Cl-bearing molecules provides key constraints for the chlorine chemistry in the diffuse gas.
Additional Information
© 2013 American Astronomical Society. Received 2012 July 20; accepted 2013 February 26; published 2013 March 26. HIFI has been designed and built by a consortium of institutes and university departments from across Europe, Canada, and the United States (NASA) under the leadership of SRON, Netherlands Institute for Space Research, Groningen, The Netherlands, and with major contributions from Germany, France, and the US. Consortium members are Canada: CSA, U. Waterloo; France: CESR, LAB, LERMA, IRAM; Germany: KOSMA, MPIfR, MPS; Ireland: NUI Maynooth; Italy: ASI, IFSI-INAF, Osservatorio Astrofisico di Arcetri-INAF; The Netherlands: SRON, TUD; Poland: CAMK, CBK; Spain: Observatorio Astronomico Nacional (IGN), Centro de Astrobiologia; Sweden: Chalmers University of Technology - MC2, RSS & GARD, Onsala Space Observatory, Swedish National Space Board, Stockholm University - Stockholm Observatory; Switzerland: ETH Zurich, FHNW; USA: CalTech, JPL, NHSC. Support for this work was provided by the Centre National de Recherche Spatiale (CNES), by the SCHISM project (grant ANR-09-BLAN-0231-01), by NASA through an award issued by JPL/Caltech, and by the Spanish MICINN (grants AYA2009-07304 and CSD2009-00038). This research has been supported in part by the NSF, award AST-0540882 to the CSO. Facility: Herschel (HIFI).Attached Files
Published - 0004-637X_767_1_81.pdf
Submitted - 1302.6616v1.pdf
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Additional details
- Eprint ID
- 38268
- Resolver ID
- CaltechAUTHORS:20130503-141900637
- Centre National de la Recherche Scientifique (CNRS)
- ANR-09- BLAN-0231-01
- Agence Nationale pour la Recherche (ANR)
- NASA/JPL/Caltech
- AYA2009-07304
- Ministerio de Ciencia e Innovación (MCINN)
- CSD2009-00038
- Ministerio de Ciencia e Innovación (MCINN)
- AST-0540882
- NSF
- Centre National d'Études Spatiales (CNES)
- Created
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2013-05-03Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field