Constraints on hot star X-ray source characteristics from combinded analysis of X-ray and UV observations

Results from wind ionization calculations are presented which show how the P-Cygni profiles of 'superionized' species such as O VI can provide information about the X-ray source characteristics of early-type stars. Using detailed radiative and atomic physics models, we find that a significant source of X-ray emission from zeta Pup comes from a region in the wind located within rougly 1 to 2 stellar radii of the photosphere. Our results suggest that X-rays sources in which emission occurs exclusively at large radii (r greater than or approximately equal to a few R(sub *)) are inconsistent with UV P-Cygni profiles for O VI. Instead, we find that X-ray emission from shocks distributed throughout the lower regions of the wind (r approximately equal to 1-2 R(sub *)) is consistent with both X-ray and UV data, as well as mass loss rates deduced from radio and H-alpha observations.