Accretion of stellar winds in high-mass X-ray binaries

Our analysis of optical spectroscopy of high-mass X-ray binaries like Cyg X-1 confirms that most of the Balmer-lines emission anticorrelated with the X-ray flux originates from the circumstellar matter between the donor star and the accreting compact component. In order to study its structure and variability and the consequent accretion rate we have developed a 3-D numerical model based on radiation hydrodynamics of the supergiant stellar wind. The results show a non-stationary BHL-accretion on the compact component.