Gaseous Flows in Inner Regions of Circum-binary Disks of T Tauri Stars

摘要

We present results of 2D and 3D numerical simulations of the matter flow in the circum-binary disk of a binary T Tauri star. It is shown that two bow shocks caused by the supersonic motion of the binary components in the gas of the disk are formed in the system. These bow shocks significantly change the flow pattern. In particular, in the inner region of the system the velocity distribution is far from the Keplerian one and the flow structure is mainly governed by the bow shocks. Presence of the stationary bow shocks leads to formation of a gap, rarefied region in the circum-binary disk having a radius of ～3 A (A is the average binary separation) for systems with the zero eccentricity and ～3.2 A for systems with the larger eccentricity. The angular momentum is removed from the system mainly due to the bow shocks. As a consequence two spiral flows form. Matter flows into the system only from the head-on collision point. The flow toward the low mass component is ～ 1.5 times higher than the same flow toward the massive component. At the same time the interaction of the flow structure elements leads to redistribution of the angular momentum and, consequently, to the higher rate of accretion onto the massive component (M_1/M_2 ～ 1.4).