Three-dimensional hydrodynamical modeling of mass transfer in the close binary system beta Lyr

摘要

We present a three-dimensional hydrodynamical modeling of mass transfer ill the close binary system beta Lyr taking radiative cooling into account explicitly. The assumed mass-transfer rate through the first Lagrangiau point L-1 is 3.0 x 10(-5) M-circle dot/yr. A flow with a radius of 0.14-0.16 (ill units of orbital separation) is formed in the vicinity of L-1. This flow forms all accretion disk with a radius close to 23 R-circle dot and a thickness of about 10 R-circle dot. The accretion disk is surrounded by all Outer envelope that extends beyond the Computational domain. A spiral shock forms at the outer boundary of the disk at orbital phase 0.25. Geometrically, the disk is toruslike, while the outer envelope is cylinder-like. In this model, which has low temperatures inside the computational domain, no jetlike Structures form ill the disk. It is possible that the jetlike Structure in beta Lyr arises due to the interaction of radiative wind from the accretor with the flow from L-1. In the model considered, a hot region exists over the poles of the accretor at a height of about 0.21. The amount of matter lost by the system is close to 10% of the mass flowing through L-1; i.e., the mass transfer in the system is almost conservative. For a mass-transfer rate of 3.0 x 10(-5) M-circle dot/yr, the orbital period varies by 40.4 s/yr. This means that the observed variation of the orbital period of 19 s/yr should correspond to a mass-transfer rate close to 1.0 x 10(-5) M-circle dot/yr.