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A weak diffuse interstellar band in the far-ultraviolet spectrum of zeta Ophiuchi?Goddard High Resolution Spectrograph (GHRS) observations at 3.5 km/s resolution reveal several new weak unidentified interstellar absorption lines in the ultraviolet spectrum of zeta Ophiuchi. The unidentified line at 1369.13 A has the appearance and characteristics of a weak diffuse interstellar band (DIB). The line has a smooth profile similar to many optical diffuse interstellar bands (i.e., a shallow asymmetric profile), it is clearly broader than identified interstellar lines near it in wavelength, and its full width at half maximum in ergs is comparable to the widths of the weak optical DIBs. The asymmetric profile cannot be attributed to blended absorption from diffuse clouds at different velocities; at this resolution the two principal cloud complexes on the sight line at heliocentric velocities of -27 and -15 km/s are clearly separated. We compare this unidentified absorption feature to identified interstellar atomic and molecular absorption lines and optical DIBs observed on the zeta Oph and xi Per sight lines, and we conclude that it is reasonable to suggest that this absorption feature might be a DIB. This is not a unique interpretation however; the unidentified line could alternatively be due to gas in the zeta Oph H II region or a blend of unknown neutral atomic or molecular absorption lines.
Document ID
19950034202
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Tripp, Todd M.
(Univ. of Wisconsin-Madison, Madison, WI United States)
Cardelli, Jason A.
(Univ. of Wisconsin-Madison, Madison, WI United States)
Savage, Blair D.
(Univ. of Wisconsin-Madison, Madison, WI United States)
Date Acquired
August 16, 2013
Publication Date
February 1, 1994
Publication Information
Publication: Astronomical Journal
Volume: 107
Issue: 2
ISSN: 0004-6256
Subject Category
Astronomy
Accession Number
95A65801
Funding Number(s)
CONTRACT_GRANT: NGT-51003
CONTRACT_GRANT: NAGW-2520
CONTRACT_GRANT: NAS5-29638
Distribution Limits
Public
Copyright
Other

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