Multicomponent radiatively driven stellar winds - II. Gayley-Owocki heating in multitemperature winds of OB stars

We show that the so-called Gayley-Owocki (Doppler) heating is important for the temperature structure of the wind of main sequence stars cooler than t he spectral type O6. The formula for Gayley-Owocki heating is derived direc tly from the Boltzmann equation as a direct consequence of the dependence o f the driving force on the velocity gradient. Since Gayley-Owocki heating d eposits heat directly on the absorbing ions, we also investigated the possi bility that individual components of the radiatively driven stellar wind ha ve different temperatures. This effect is negligible in the wind of O stars , whereas a significant temperature difference takes place in the winds of main sequence B stars for stars cooler than B2. Typical temperature differe nces between absorbing ions and other ow components for such stars is of th e order 10(3) K. However, in the case when the passive component falls back onto the star, the absorbing component reaches temperatures of order 10(6) K, which allows for emission of X-rays. Moreover, we compare our computed terminal velocities with the observed ones. We found quite good agreement b etween predicted and observed terminal velocities. The systematic differenc e coming from the using of the so called "cooking formula" has been removed .