GRAVITATIONAL MICROLENSING OF BINARY STARS - LIGHT-CURVE SYNTHESIS

A method is described for calculating the Light curve for a physical s tellar binary system microlensed by a dark body in the Galactic halo, taking into account tidal-rotational deformation of the stars, their m utual heating, limb darkening, and gravitational darkening. Model ligh t curves are calculated for the cases of point and extended gravitatio nal lenses and binary systems located in the Large Magellanic Cloud an d in the Galactic bulge. The binarity of the stellar system is clearly observable for some combinations of the system parameters, especially for binaries in the Galactic bulge. In many cases, the microlensing c urves for a binary with stars with nonzero angular sizes differ from t hose for a system of two point sources. The prospects for studying mic rolensing of binary background stars in order to reveal differences be tween compact and extended gravitational lenses are discussed.