Microlensing and polarization

The discovery of the microlensing effect has found out the new population — dark bodies having mass of the order of 0.1M which form the halo of our Galaxy. There are two main criteria which identify a light curve as the reveal of the microlensing effect. They are symmetry of the light curve and equal amplification in different colors. We consider polarization of the light beam arising in microlensing effect and find that additional test is possible — polarization of light in the case of a finite star disk. Consequences of polarization are also considered.