MEASURING THE NUMBER OF M DWARFS PER M DWARF USING KEPLER ECLIPSING BINARIES

• Published in: The Astrophysical journal Vol. 813; no. 1; pp. 75 - 91
• Main Authors: Shan, Yutong, Johnson, John A., Morton, Timothy D.
• Format: Journal Article
• Language: English
• Published: The American Astronomical Society 01-11-2015
• Subjects: binaries: close; binaries: eclipsing; Binary stars; Eclipsing binary stars; methods: observational; methods: statistical; Orbitals; Photometry; Red dwarf stars; Samples; stars: low-mass; Statistical methods; techniques: photometric; Transits
• ISSN: 0004-637X; 1538-4357; 1538-4357
• DOI: 10.1088/0004-637X/813/1/75

ABSTRACT We measure the binarity of detached M dwarfs in the Kepler field with orbital periods in the range of 1-90 days. Kepler's photometric precision and nearly continuous monitoring of stellar targets over time baselines ranging from 3 months to 4 years make its detection efficiency for eclipsing binaries nearly complete over this period range and for all radius ratios. Our investigation employs a statistical framework akin to that used for inferring planetary occurrence rates from planetary transits. The obvious simplification is that eclipsing binaries have a vastly improved detection efficiency that is limited chiefly by their geometric probabilities to eclipse. For the M-dwarf sample observed by the Kepler Mission, the fractional incidence of eclipsing binaries implies that there are close stellar companions per apparently single M dwarf. Our measured binarity is higher than previous inferences of the occurrence rate of close binaries via radial velocity techniques, at roughly the 2 level. This study represents the first use of eclipsing binary detections from a high quality transiting planet mission to infer binary statistics. Application of this statistical framework to the eclipsing binaries discovered by future transit surveys will establish better constraints on short-period M+M binary rate, as well as binarity measurements for stars of other spectral types.