Light Curve Synthesis for Colliding-Wind Binary Systems

The synthesis method which allows one to compute light curves of binary systems in the Roche model is a powerful and widely used analysis tool. However, in its original form, it is not suitable for the analysis of light curves of binary systems in which one or both components have powerful stellar winds. Previously, we proposed a model of a binary system based on the synthesis method and including one component with a wind. In the current paper, we propose a generalization of the model to the case when both components of the binary system have winds. The surface separating the two winds (the contact surface) is calculated within the framework of a steady state model of stellar wind collision. When calculating the light curve, the absorption of stellar radiation in the winds, as well as in the cooling layers located on both sides of the contact surface, is taken into account. The structure of the cooling layers and their surface density are calculated in the radiative shock limit. The algorithm allows one to take into account the asymmetry of the contact surface caused by the Coriolis force, as well as (using pre-calculated tables) the radiative inhibition of the winds in close binary systems. The results of numerical calculations in various test models are presented, clearly demonstrating the need to take into account the influence of the winds on optical light curves in WR + WR, WR + O, and O + O systems.