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   PR # 22020
    We propose to use ASCA SIS to observe four B stars which are known   
    from ROSAT observations to be overluminous for their spectral types. 
    This class of stars, exemplified by tau Sco (B0 V), is characterized 
    by X-ray spectra which are harder than those of other B stars.  The  
    unprecedented spectral resolution of the SIS instrument will enable  
    us to differentiate line and continuum emission, and to separate the 
    strongest emission lines in the spectrum.  With these data we will   
    reconstruct the temperature distribution in these sources and search 
    for time variability in individual spectral features.  These         
    quantities will allow us to differentiate among the possible         
    mechanisms of B star X-ray production: wind shocks, coronal emission,
   and the inverse compton model 
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