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The 'Baldwin Effect' in Wolf-Rayet starsThe equivalent widths of a number of emission lines in the spectra of WN-type Wolf-Rayet stars are found to inversely correlate with the luminosity of the underlying continuum. This is the well-known Baldwin Effect that has previously been observed in quasars and some Seyfert I galaxies. The Effect can be inferred from line and continuum predictions in published non-LTE model helium atmospheres and is explainable in terms of differences in wind density among WN stars. Using a simple wind model, we show that the Effect arises from the fact that both the effective radius for the local continuum and the emission measure of the layers above the continuum-forming region depend on the density in the wind. The Effect provides a new method for distance determinations of W-R stars.
Document ID
19930071271
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Morris, Patrick
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Conti, Peter S.
(Joint Inst. for Lab. Astrophysics Boulder, CO, United States)
Lamers, Henny J. G. L. M.
(Utrecht State Univ.; SRON, Lab. for Space Research, Netherlands)
Koenigsberger, Gloria
(Univ. Nacional Autonoma de Mexico Coyoacan, United States)
Date Acquired
August 16, 2013
Publication Date
September 1, 1993
Publication Information
Publication: Astrophysical Journal, Part 2 - Letters
Volume: 414
Issue: 1
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
93A55268
Funding Number(s)
CONTRACT_GRANT: NSF AST-90-15240
CONTRACT_GRANT: NAG5-1016
Distribution Limits
Public
Copyright
Other

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