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A classification system for O-B2 stars based on the Si IV and C IV resonance linesLow-dispersion ultraviolet spectra from Skylab Experiment S-019 are used to explore the variations of Si IV and C IV line strengths with temperature and luminosity. These considerations lead to a classification system in which the Si/C ratio is used to discriminate luminosity among the O stars and temperature among the O9-B2 stars of lower luminosity. Stars falling in these two regimes may be distinguished either by the presence of C IV emission or on the basis of C IV absorption strength. The log(Si IV/C IV) vs C IV diagram is proposed as a primary tool in such a classification system. The rapid variation in the Si IV/C IV ratio from less than 1/10 at O9 to greater than 10 at B1.5 for luminosity class III-V stars appears to be an especially useful criterion for the temperature classification of stars in this spectral range.
Document ID
19820032682
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Henize, K. G.
(NASA Johnson Space Center Houston, TX, United States)
Wray, J. D.
(Texas Univ. Austin, TX, United States)
Parsons, S. B.
(Texas, University Austin, TX, United States)
Date Acquired
August 10, 2013
Publication Date
November 1, 1981
Publication Information
Publication: Astronomical Journal
Volume: 86
Subject Category
Astronomy
Accession Number
82A16217
Funding Number(s)
CONTRACT_GRANT: NSG-7371
CONTRACT_GRANT: NAS8-13176
CONTRACT_GRANT: NAS8-31459
CONTRACT_GRANT: NAS9-13176
CONTRACT_GRANT: NSG-5337
Distribution Limits
Public
Copyright
Other

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