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arXiv · 2209.04214

Hunting for red supergiant binaries: UVIT photometry of the SMC

L. R. Patrick·D. Thilker·D. J. Lennon·L. Bianchi·A. Schootemeijer·R. Dorda·N. Langer·I. Negueruela
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Abstract

We present UVIT/Astrosat UV photometry of the RSG population of the Small Cloud galaxy (SMC). As RSGs are extremely faint in the far-UV, these observations directly probe potential companion stars. From a sample of 861 SMC RSGs, we find 88 have detections at far-UV wavelengths: a clear signature of binarity. Stellar parameters are determined for both components, which allows us to study - for the first time - the mass-ratio (q) distribution of RSG binary systems. We find a flat mass-ratio distribution best describes the observations up to M{RSG}~15 Msun. We account for our main observing bias (i.e. the limiting magnitude of the UVIT survey) to determine the intrinsic RSG binary fraction of 18.8+/-1.5 %, for mass-ratios in the range 0.3 < q < 1.0 and orbital periods approximately in the range 3 < log P[ days] < 8.

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L. R. Patrick, D. Thilker, D. J. Lennon, L. Bianchi, A. Schootemeijer, R. Dorda, N. Langer, I. Negueruela. 2022-09-09. Hunting for red supergiant binaries: UVIT photometry of the SMC. https://arxiv.org/abs/2209.04214

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