Triple-star Candidates among the Kepler Binaries
Abstract
We present the results of a search through the photometric database of Kepler eclipsing binaries looking for evidence of hierarchical triple-star systems. The presence of a third star orbiting the binary can be inferred from eclipse timing variations. We apply a simple algorithm in an automated determination of the eclipse times for all 2157 binaries. The "calculated" eclipse times, based on a constant period model, are subtracted from those observed. The resulting O - C (observed minus calculated times) curves are then visually inspected for periodicities in order to find triple-star candidates. After eliminating false positives due to the beat frequency between the ~1/2 hr Kepler cadence and the binary period, 39 candidate triple systems were identified. The periodic O - C curves for these candidates were then fit for contributions from both the classical Roemer delay and so-called physical delay, in an attempt to extract a number of the system parameters of the triple. We discuss the limitations of the information that can be inferred from these O - C curves without further supplemental input, e.g., ground-based spectroscopy. Based on the limited range of orbital periods for the triple-star systems to which this search is sensitive, we can extrapolate to estimate that at least 20% of all close binaries have tertiary companions.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- May 2013
- DOI:
- 10.1088/0004-637X/768/1/33
- arXiv:
- arXiv:1302.0563
- Bibcode:
- 2013ApJ...768...33R
- Keywords:
-
- binaries: close;
- binaries: eclipsing;
- binaries: general;
- celestial mechanics;
- stars: formation;
- stars: statistics;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 19 pages, 13 figures, 3 tables