The effects of coronal regions on the X-ray flux and ionization conditions in the winds of OB supergiants and Of stars

Abstract

Auger ionization by X-rays emanating from a thin coronal zone at the base of cool stellar winds may account for the strong O VI and N V lines in O stars and the C IV lines in B supergiants. This hypothesis is supported by the study of the corona size needed to produce the overall ionization conditions prevailing in Zeta Puppis. A coronal zone with a volume emission measure of 10 to the 58th power per cu cm and a temperature of five million deg K yields the required ionization. X-ray flux data from satellite observations also supports the hypothesis.