Orbital circularization of Kepler eclipsing bin.

Observing this effect is challenging because it requires large and well-characterized samples that include both hot and cool stars. Here we seek evidence of the predicted dependence of circularization upon stellar type, using a sample of 945 eclipsing binaries observed by Kepler.

This sample complements earlier studies of this effect, which employed smaller samples of better-characterized stars. For each Kepler binary we measure e.cos.{omega} based on the relative timing of the primary and secondary eclipses. We examine the distribution of e.cos.{omega} as a function of period for binaries composed of hot stars, cool stars, and mixtures of the two types.