Kepler Eclipsing Binary Stars. IV. Precise Eclipse Times for Close Binaries and Identification of Candidate Three-Body Systems

TL;DR

This paper provides a catalog of precise eclipse timings for 1279 close binaries from Kepler data, identifies 236 systems with potential third bodies, and develops methods to analyze distorted light curves for third-body signals.

Contribution

It introduces a new method to measure eclipse times in distorted light curves and identifies candidate third-body systems among close binaries.

Findings

236 systems show timing variations compatible with third bodies

Developed a method for precise eclipse timing in distorted light curves

Provides comprehensive eclipse timings for all Kepler close binaries

Abstract

We present a catalog of precise eclipse times and analysis of third body signals among 1279 close binaries in the latest Kepler Eclipsing Binary Catalog. For these short period binaries, Kepler's 30 minute exposure time causes significant smearing of light curves. In addition, common astrophysical phenomena such as chromospheric activity, as well as imperfections in the light curve detrending process, can create systematic artifacts that may produce fictitious signals in the eclipse timings. We present a method to measure precise eclipse times in the presence of distorted light curves, such as in contact and near-contact binaries which exhibit continuously changing light levels in and out of eclipse. 236 systems for which we find a timing variation signal compatible with the presence of a third body are identified. These are modeled for the light time travel effect and the basic properties of the third body are derived. This study complements Orosz et al. (2013; in prep), which focuses on eclipse timing variations of longer period binaries with flat out-of-eclipse regions. Together, these two papers provide comprehensive eclipse timings for all binaries in the Kepler Eclipsing Binary Catalog, as an ongoing resource freely accessible online to the community.