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Chandra high energy resolution observations have now been obtained fromnumerous non-peculiar O and early B stars. The observed X-ray emission lineproperties differ from pre-launch predictions, and the interpretations arestill problematic. We present a straightforward analysis of a broad collectionof OB stellar line profile data to search for morphological trends. X-ray lineemission parameters and the spatial distributions of derived quantities areexamined with respect to luminosity class. The X-ray source locations and theircorresponding temperatures are extracted by using the He-like f/i line ratiosand the H-like to He-like line ratios respectively. Our luminosity class studyreveals line widths increasing with luminosity. Although the majority of the OBemission lines are found to be symmetric, with little central linedisplacement, there is evidence for small, but finite, blue-ward line-shiftsthat also increase with luminosity. The spatial X-ray temperature distributionsindicate that the highest temperatures occur near the star and steadilydecrease outward. This trend is most pronounced in the OB supergiants. For thelower density wind stars, both high and low X-ray source temperatures existnear the star. However, we find no evidence of any high temperature X-rayemission in the outer wind regions for any OB star. Since the temperaturedistributions are counter to basic shock model predictions, we call this the"near-star high-ion problem" for OB stars. By invoking the traditional OBstellar mass loss rates, we find a good correlation between the fir-inferredradii and their associated X-ray continuum optical depth unity radii. Weconclude by presenting some possible explanations to the X-ray source problemsthat have been revealed by this study.

astrophysical journal/the astrophysical journal

An Extensive Collection of Stellar Wind X-ray Source Region Emission  Line Parameters,Temperatures, Velocities, and Their Radial Distributions as  Obtained from Chandra Observations of 17 OB Stars