%0 Journal Article
%T New RR Lyrae variables in binary systems
%A G. Hajdu
%A M. Catelan
%A J. Jurcsik
%A I. D¨¦k¨¢ny
%A A. J. Drake
%A J. -B. Marquette
%J Physics
%D 2015
%I arXiv
%R 10.1093/mnrasl/slv024
%X Despite their importance, very few RR Lyrae (RRL) stars have been known to reside in binary systems. We report on a search for binary RRL in the OGLE-III Galactic bulge data. Our approach consists in the search for evidence of the light-travel time effect in so-called observed minus calculated ($O-C$) diagrams. Analysis of 1952 well-observed fundamental-mode RRL in the OGLE-III data revealed an initial sample of 29 candidates. We used the recently released OGLE-IV data to extend the baselines up to 17 years, leading to a final sample of 12 firm binary candidates. We provide $O-C$ diagrams and binary parameters for this final sample, and also discuss the properties of 8 additional candidate binaries whose parameters cannot be firmly determined at present. We also estimate that $\gtrsim 4$ per cent of the RRL reside in binary systems.
%U http://arxiv.org/abs/1502.01318v1