Period Change of Eclipsing Binaries from the ASAS Catalog

Abstract

We present a preliminary statistical analysis of a period change of eclipsing binaries from the ASAS Catalog of Variable Stars. For each contact and semidetached system brighter than 13.3$mag$ (in V) with a period shorter than 0.4 days and at least 300 observation points we have found an angular velocity $\omega$ and its time derivative $\frac{d\omega}{dt}$. According to our accuracy there is no evidence that average $\frac{d\omega}{dt}$ differs from 0. Light curves for selected stars are presented.