Formation of resonance spectral line profiles in stellar wind: Theory and observations

Abstract

The theory of the formation of resonance spectral line profiles in the stellar wind of hot stars has been elaborated taking into account the presence of microturbulent motions. In this case the local frequency redistribution in the line profile function is incomplete. This circumstance generates dominating backscattering of photons and drastic changes in the resonance line profiles, including the presence of wide dark plateaux in the central region of the profile. It also modifies essentially the dynamics of the radiatively driven stellar wind. The resonance spectral line profiles, their variability and DACs in them have been analysed based on IUE spectra of a set of B supergiants and on the theoretical concepts.