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Empirical mass-loss rates for 25 O and early B stars, derived from Copernicus observationsUltraviolet line profiles are fitted with theoretical line profiles in the cases of 25 stars covering a spectral type range from O4 to B1, including all luminosity classes. Ion column densities are compared for the determination of wind ionization, and it is found that the O VI/N V ratio is dependent on the mean density of the wind and not on effective temperature value, while the Si IV/N V ratio is temperature-dependent. The column densities are used to derive a mass-loss rate parameter that is empirically correlated against the mass-loss rate by means of standard stars with well-determined rates from IR or radio data. The empirical mass-loss rates obtained are compared with those derived by others and found to vary by as much as a factor of 10, which is shown to be due to uncertainties or errors in the ionization fractions of models used for wind ionization balance prediction.
Document ID
19810059444
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gathier, R.
(Groningen Rijksuniversiteit, Groningen, Netherlands)
Lamers, H. J. G. L. M.
(Space Research Astronomical Observatory Utrecht, Netherlands)
Snow, T. P.
(Colorado, University Boulder, CO, United States)
Date Acquired
August 11, 2013
Publication Date
July 1, 1981
Publication Information
Publication: Astrophysical Journal
Subject Category
Astrophysics
Accession Number
81A43848
Funding Number(s)
CONTRACT_GRANT: NAG5-15
CONTRACT_GRANT: NSG-5355
Distribution Limits
Public
Copyright
Other

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