Waves in Accretion Disks in Close Binary Stars

摘要

Three-dimensional numerical simulations of gas dynamics are used to study the flow pattern in a close binary system after it has reached the steady-state accretion regime. The special attention is paid to physics of accretion disks in binary systems and. particularly, the waves in disks. It is shown that in systems with stationary accretion disks there are shock waves: how shock caused by the motion of the accretor and disk in the gas of the circumbinary envelope; "hot line" formed due to interaction between the circum-disk halo and stream from the inner Lagrange point LI, and two arms of the tidal shock. Gas dynamic simulations combined with Doppler tomograms allow us to identify all these shocks. Indeed, in tomograms of SS Cyg during its quiescent state the luminosity is maximum at the arms of the spiral tidal shock, at the "hot line," and in the region behind the bow shock. The characteristic features and possible observational manifestations of the precessional spiral density wave formed in the disk arc also discussed.