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.
@article{arxiv.1609.06474,
title = {KIC 2831097 - A 2-year orbital-period RR Lyrae binary candidate},
author = {Á. Sódor and M. Skarka and J. Liška and Zs. Bognár},
journal= {arXiv preprint arXiv:1609.06474},
year = {2016}
}
Comments
Accepted for publication in MNRAS Letters. 5 pages, 5 figures, 2 tables