A Search for Hierarchical Triples using Kepler Eclipse Timing

TL;DR

This study used Kepler eclipse timing data to search for third star companions in 41 eclipsing binaries, finding long-term variations suggestive of tertiary companions, supporting theories of binary formation involving third stars.

Contribution

First Kepler survey targeting eclipse timing variations to identify tertiary companions in eclipsing binaries, revealing long-term timing variations indicative of third stars.

Findings

34% of binaries show long-term timing variations

No short-period third companions detected

Results support formation theories involving third stars

Abstract

We present the first results of a Kepler survey of 41 eclipsing binaries that we undertook to search for third star companions. Such tertiaries will periodically alter the eclipse timings through light travel time and dynamical effects. We discuss the prevalence of starspots and pulsation among these binaries and how these phenomena influence the eclipse times. There is no evidence of short period companions (P < 700 d) among this sample, but we do find evidence for long term timing variations in 14 targets (34%). We argue that this finding is consistent with the presence of tertiary companions among a significant fraction of the targets, especially if many have orbits measured in decades. This result supports the idea that the formation of close binaries involves the deposition of angular momentum into the orbital motion of a third star.