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Ultraviolet photometry from the orbiting astronomical observatory. XVI - The stellar Lyman-alpha absorption lineThe stellar Lyman-alpha line at 1216 A was observed in 29 lightly reddened stars of spectral type B2.5 to B9 by a far-UV spectrophotometer on OAO-2. The equivalent widths obtained range from 15 A at type B2.5 to 65 A at type B8; in the late-B stars, the L-alpha line removes 2 to 3% of the total stellar flux. In this sampling, the strength of the L-alpha line correlates well with measures of the Balmer discontinuity and Balmer line strengths; luminosity classification does not seem to affect the line strength. The observed line widths also agree with the predictions of Mihala's grid of non-LTE model atmospheres. In some cases, the L-alpha line influences the interstellar column densities reported in the interstellar OAO-2 L-alpha survey. Hence, these data toward lightly reddened B2 and B1.5 stars should be regarded as upper limits only.
Document ID
19740057005
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Savage, B. D.
Panek, R. J. (Washburn Observatory Madison, Wis., United States)
Date Acquired
August 7, 2013
Publication Date
August 1, 1974
Publication Information
Publication: Astrophysical Journal
Volume: 191
Subject Category
SPACE SCIENCES
Funding Number(s)
CONTRACT_GRANT: NAS5-1348
Distribution Limits
Public
Copyright
Other