Mass and angular momentum loss from contact binary systems

Abstract

Gas outflows from contact binary systems are calculated using a generalized curvilinear coordinate system and the implicit factored scheme. The former technique allows us to treat the complicated shape of the boundary of the binary system in a simple manner. The latter leads to larger integration time-steps than conventional explicit schemes and results in the efficiency of the simulation. The obtained flow field shows the spiral pattern of ejected gas clouds which drift out through the outer Lagrangian points. These clouds escape from the system with angular momentum. A specific angular momentum loss from the system is estimated to be about 1.65 ± 0.1 which is compatible with the value computed based on restricted three-body problems.