BEER analysis of CoRoT light curves

Optimizing the Anglo-Australian-Telescope pointing coordinates and the AAOmega fiber-allocations with dedicated softwares, we acquired 6-7 medium-resolution spectra of 281 candidates in a seven-night campaign. Analysis of the red-arm AAOmega spectra, which covered the range of 8342-8842{AA}, yielded a radial-velocity precision of ~1 km/s. Spectra containing lines of more than one star were analyzed with the two- dimensional correlation algorithm TODCOR.

The measured radial velocities confirmed the binarity of seventy of the BEER candidates, 45 single-line binaries, 18 double-line binaries, and 7 diluted binaries. We show that red giants introduce a major source of false candidates and demonstrate a way to improve BEER's performance in extracting higher fidelity samples from future searches of CoRoT lightcurves. The periods of the confirmed binaries span a range of 0.3-10days and show a rise in the number of binaries per logP bin toward longer periods.

The estimated mass ratios of the double-line binaries and the mass ratios assigned to the single-line binaries, assuming an isotropic inclination distribution, span a range of 0.03-1. On the low-mass end we have detected two brown-dwarf candidates on a ~1day period orbit. This is the first time non-eclipsing beaming binaries are detected in CoRoT data, and we estimate that ~300 such binaries can be detected in the CoRoT long-run lightcurves.