Solving light curves of WR+O binaries: the regularization approach
Sternberg State Astronomical Institute, Moscow State University, Moscow, Russian Federation
Abstract
Extended semi-transparent atmospheres of WR stars in eclipsing WR+O binaries present some difficulties for analysis of their light curves. We present an approach to the problem based on solving the most general form of integral equations describing a light curve of a WR+O binary: Fredholm’s equations of the first kind. The unknown functions are the brightness and opacity distributions across the disk of the WR component. The equations represent an ill-posed problem. To get a stable, unique solution one needs to impose some a priori constraints on the solution. We review various physically justified sets of constraints and, using artificially simulated light curves with known solutions, show how these constraints and the so-called regularization technique work to retrieve the functions of interest. The influence of errors in the input light curve on the solution is shown and discussed. The algorithms and the corresponding computer programs are open to the scientific community.