Gas Dynamic Simulations of Inner Regions of Protoplanetary Disks in Young Binary Stars

Abstract

We have carried out 2D and 3D numerical simulations (Kaigorodov et al. 2010 of accretion processes in binary T Tauri stars (TTSs) DQ Tau, UZ Tau E, V4046 Sgr, GW Ori, RoXs 42C using a finite-difference Roe-Osher-Einfeld TVD scheme. The morphology of the flow pattern for UZ Tau E is shown in Fig. 1 (left panel). The flow structure includes accretion disks surrounding the components, bow-shocks in front of both the components, a shock wave ("bridge") between the circumstellar accretion disks and a gap containing rarefied gas in the inner part of the protoplanetary disk.The performed simulations show that the radii of the gaps which formed due to the bow-shocks fit the observations better than the radii calculated using positions of the Linblad resonances according to Artymowicz & Lubow (1994). For systems with circular orbits, the calculated gap radius is ∼ 3A (A -semi-major axis of the system) and for those with elliptic orbits it is ∼ 3.2 -3.3A. Thus, the bow-shocks govern the size and shape of the gap in young binary systems.Analysis of the fluxes demonstrates that the re-distribution of the angular momentum in the envelope due to the bow-shocks leads to occurrence of two flows propagating from the inner edge of the protoplanetary disk to the components (see Fig. 1, right panel). Let us consider streams near the less massive star (secondary). The matter in the gap splits into two streams at the head-on collision point when passing through the bow-shock. The first portion of matter (stream A in Fig. 1, right panel) loses its angular momentum at the shock and starts to move toward the circumstellar accretion disk forming a spiral flow. The second portion of matter