Место издания:Astronomical Society of the Pacific San Francisco
Первая страница:408
Последняя страница:412
Аннотация:As a result of our multi-year study of the photometric and spectral variability of Cyg X-1, we have established that the mean level of star brightness continues to decrease since 1999 with the variations on smaller time scales superimposed. Our spectral observations with the 6 meter and 1 meter telescopes of the SAO RAS show variations of absorption line depths. There is a connection between X-ray and optical changes, which suggests that the fundamental parameters of the supergiant in the system of Cyg X-1 are varying. There are evidences of a possible presence of a variable optically thin gas in the system.