Kepler Eclipsing Binaries with Stellar Companions

Abstract

Many short-period binary stars have distant orbiting companions that have played a role in driving the binary components into close separation. Indirect detection of a tertiary star is possible by measuring apparent changes in eclipse times of eclipsing binaries as the binary orbits the common center of mass. Here we present an analysis of the eclipse timings of 41 eclipsing binaries observed throughout the NASA Kepler mission of long duration and precise photometry. This subset of binaries is characterized by relatively deep and frequent eclipses of both stellar components. We present preliminary orbital elements for seven probable triple stars among this sample, and we discuss apparent period changes in seven additional eclipsing binaries that may be related to motion about a tertiary in a long period orbit. The results will be used in ongoing investigations of the spectra and light curves of these binaries for further evidence of the presence of third stars.

Orbital Period Investigations of Two W UMa-type Binaries: AH Aur and V728 Her

“…In such a case, it is possible that there is a long-period third star in the system causing the periodic variations of their orbital periods. For example, Gies et al (2015) have found several detached eclipsing binaries in the Kepler field where the mass transfer process can be rejected due to their detached configurations, so a tertiary companion is the cause of the variations. However, if the orbital period of the third star is very long, it would be difficult to confirm the tertiary hypothesis.…”