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Narrow components in the profiles of ultraviolet resonance lines - Evidence for a two-component stellar wind for O and B starsThe presence of narrow, shifted absorption features superposed on the wide P Cygni profiles of the UV resonance lines in the spectra of O and B stars is studied and possible explanations of the narrow components are discussed. Spectra from 26 stars of spectral types O4f to B1 Ib were examined for the presence of narrow components in the absorption part of the profiles, and positive evidence was detected in 17. The central velocities of the features are found to be similar for different ions of the same star, and typically equal to 0.75 times the terminal velocity of the stellar wind. The width of the narrow absorptions is about 18% of the terminal stellar wind velocity, with a column density generally not correlated with the effective temperature or mass loss rate. Possible explanations for the narrow components include peaks in the degree of ionization, a stationary stellar shell, a plateau in the stellar wind velocity law, a decelerating stellar wind, a variable mass loss rate or a two component stellar wind with low-velocity, low-density material found at a distance greater than 2 stellar radii, which explanation appears most likely.
Document ID
19820053726
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lamers, H. J. G. L. M.
(Utrecht State Univ. Netherlands)
Gathier, R.
(Utrecht Rijksuniversiteit, Utrecht, Netherlands)
Snow, T. P., Jr.
(Colorado, University Boulder, CO, United States)
Date Acquired
August 10, 2013
Publication Date
July 1, 1982
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
82A37261
Funding Number(s)
CONTRACT_GRANT: NAG5-15
Distribution Limits
Public
Copyright
Other

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