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Diffuse Interstellar Bands Toward HD 62542

Ádámkovics, Máté and Blake, Geoffrey A. and McCall, Benjamin J. (2005) Diffuse Interstellar Bands Toward HD 62542. Astrophysical Journal, 625 (2). pp. 857-863. ISSN 0004-637X. doi:10.1086/429813.

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Diffuse interstellar bands (DIBs) have been detected for the first time along the peculiar translucent line of sight toward HD 62542, which passes through a diffuse cloud core. Although only a small fraction (18 out of more than 300) of generally weak DIB features have been shown to correlate with C_2 and C_3 (the "C_2 DIBs"), it is predominantly these DIBs that are observed toward HD 62542. The typically strong DIBs λλ5780 and 5797 are detected but are significantly weaker than toward other lines of sight with similar reddening. Other commonly observed DIBs (such as λλ4430, 6270, and 6284) remain noticeably absent. These observations further support the suggestion that the line of sight toward HD 62542 crosses only the core of a diffuse cloud and show that the correlation between the C_2 DIBs and small carbon chains is maintained in environments with very large fractions of molecular hydrogen, f_(H_2) > 0.8. A comparison of CH, CN, C_2, and C_3 column densities and C_2 DIB strengths toward HD 62542, HD 204827, and HD 172028 suggests that the line of sight toward HD 204827 passes through a diffuse cloud core similar to that seen toward HD 62542, as well as what might be referred to as a diffuse cloud envelope. This indicates that the bare core toward HD 62542 may not have significantly different relative chemical abundances from other diffuse cloud cores and that the C_2 DIBs may serve as a diagnostic of such cores.

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Blake, Geoffrey A.0000-0003-0787-1610
Additional Information:© 2005 American Astronomical Society. Received 2003 December 1; accepted 2005 February 21. We acknowledge helpful conversations with T. P. Snow, D. E. Welty, and D.G. York, as well as the rest of the Apache Point Observatory DIB survey team, S. D. Friedman, L. M. Hobbs, T. Oka, B. L. Rachford, P. Sonnentrucker, and J. A. Thorburn, for use of their results prior to publication. The data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W. M. Keck Foundation. B. J. M. has been supported by the Miller Institute for Basic Research in Science.
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Miller Institute for Basic Research in ScienceUNSPECIFIED
Subject Keywords:astrochemistry; ISM: lines and bands; ISM: molecules
Issue or Number:2
Record Number:CaltechAUTHORS:20120918-102258580
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Official Citation:Diffuse Interstellar Bands Toward HD 62542 Máté Ádámkovics et al. 2005 ApJ 625 857
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34171
Deposited On:18 Sep 2012 18:11
Last Modified:09 Nov 2021 23:07

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