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arXiv · 1609.06474

KIC 2831097 - A 2-year orbital-period RR Lyrae binary candidate

Á. Sódor·M. Skarka·J. Liška·Zs. Bognár
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Abstract

We report the discovery of a new Kepler first-overtone RR Lyrae pulsator, KIC 2831097. The pulsation shows large, 0.1 d amplitude, systematic phase variations that can be interpreted as light travel-time effect caused by orbital motion in a binary system, superimposed on a linear pulsation-period decrease. The assumed eccentric (e=0.47) orbit with the period of approximately 2 yr is the shortest among the non-eclipsing RR Lyrae binary candidates. The binary model gives a lowest estimate for the mass of the companion of 8.4 M_Sun, that places it among black hole candidates. Beside the first-overtone pulsation, numerous additional non-radial pulsation frequencies were also identified. We detected an ~47-d Blazhko-like irregular light-curve modulation.

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Á. Sódor, M. Skarka, J. Liška, Zs. Bognár. 2016-09-21. KIC 2831097 - A 2-year orbital-period RR Lyrae binary candidate. https://doi.org/10.1093/mnrasl/slw194

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