BibTeX
@MISC{Macfarlane_d.h.cohen,,
author = {Cassinelli Macfarlane and J. J. Macfarlane},
title = {D.H. Cohen,},
year = {}
}
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Abstract
In this paper we report on ROSAT PSPC observations of 27 near-main-sequence B stars made with unprecedented sensitivity. Contrary to the results of previous surveys, it is found that 75 percent of the sample stars are X-ray sources, albeit most at modest levels. The X-ray luminosities of the program stars range from 5:6 \Theta 10 27 ergs s \Gamma1 up to 2:2 \Theta 10 32 ergs s \Gamma1 . We find that LX=L Bol decreases abruptly beyond about B0 and stabilizes at LX=L Bol ß 10 \Gamma8:5 by about B2, with seven non-detections at B2 and later. For the B0 and B1 stars our modeling suggests wind attenuation of the X-ray photons is significant, so that the emitted X-ray luminosity, corrected for this attenuation, actually exceeds 10 \Gamma7 L Bol in some cases. Presumably this situation is even more severe for O stars, thus the well known LX=L Bol ß 10 \Gamma7 law may simply be an artifact of the neglect of wind attenuation. The ROSAT PSPC observations of most of the B stars are ...
