X-ray properties of bright OB-type stars detected in the ROSAT all-sky survey
* 1, 2,
J.H.M.M. Schmitt 1,
R. Danner 1, 3 and
J.P. Cassinelli 4
Received 17 July 1996 / Accepted 26 November 1996
The ROSAT all-sky survey has been used to study the X-ray properties for all OB-type stars listed in the Yale Bright Star Catalogue. Here we present a detailed astrophysical discussion of our analysis of the X-ray properties of our complete sample of OB-type stars; a compilation of the X-ray data is provided in an accompanying paper (Berghöfer, Schmitt & Cassinelli 1996).
We demonstrate that the "canonical" relation between X-ray and total luminosity of valid for O-type stars extends among the early B-type stars down to a spectral type B1-B1.5; for stars of luminosity classes I and II the spectral type B1 defines a dividing line for early-type star X-ray emission.
We discuss the X-ray properties of X-ray detected B2-B9 stars (LC III-V) in the context of possible companions.
We also compare our results to the results obtained from Einstein Observatory data and ROSAT pointed observations. We show for our sample of stars that X-ray variability is generally not common for O-type stars as well as early B-type stars.
Key words: stars: early-type X-rays: stars stars: mass loss
Send offprint requests to: T.W. Berghöfer
© European Southern Observatory (ESO) 1997
Online publication: June 30, 1998