SIMBAD references

2013ApJ...774...81T - Astrophys. J., 774, 81 (2013/September-1)

The anticorrelated nature of the primary and secondary eclipse timing variations for the Kepler contact binaries.


Abstract (from CDS):

We report a study of the eclipse timing variations in contact binary systems, using long-cadence lightcurves from the Kepler archive. As a first step, observed minus calculated (O - C) curves were produced for both the primary and secondary eclipses of some 2000 Kepler binaries. We find ∼390 short-period binaries with O - C curves that exhibit (1) random walk-like variations or quasi-periodicities, with typical amplitudes of ±200-300 s, and (2) anticorrelations between the primary and secondary eclipse timing variations. We present a detailed analysis and results for 32 of these binaries with orbital periods in the range of 0.35±0.05 days. The anticorrelations observed in their O - C curves cannot be explained by a model involving mass transfer, which, among other things, requires implausibly high rates of ∼0.01 M_☉/yr. We show that the anticorrelated behavior, the amplitude of the O - C delays, and the overall random walk-like behavior can be explained by the presence of a starspot that is continuously visible around the orbit and slowly changes its longitude on timescales of weeks to months. The quasi-periods of ∼50-200 days observed in the O - C curves suggest values for k, the coefficient of the latitude dependence of the stellar differential rotation, of ∼0.003-0.013.

Abstract Copyright:

Journal keyword(s): binaries: eclipsing - binaries: general - stars: activity - stars: evolution - starspots - stars: rotation

Simbad objects: 40

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