INHOMOGENEITIES OF THE STELLAR WINDS OF HOT SUPERGIANTS

The causes of variability of line profiles in the spectra of 0 supergiants are analyzed. It is suggested that the main cause of the variability is the motion in the atmosphere of dense clumps of matter (inhomogeneities or clouds) along the line of sight between star and observer. The profiles of C IV and Si IV UV resonance lines in the spectra of bright OB supergiants are calculated for spherically symmetric atmospheres and for atmospheres with inhomogeneity along the line of sight. The dependence of the line profiles on the distance of the inhomogeneity from the center of the star is investigated. It is shown that the formation and evolution with time of discrete absorption components (DACs) in the profiles of C IV and Si IV UV resonance lines can be explained within the framework of the proposed model of variability of line profiles. The parameters of the inhomogeneities moving in the atmosphere to produce DACs are estimated.