Short-period Heartbeat Binaries from TESS Full-frame Images

Abstract

We identify 240 short-period ( P ≲ 10 days) binary systems in Transiting Exoplanet Survey Satellite data, 180 of which are heartbeat binaries. The sample is mostly a mix of A- and B-type stars and primarily includes eclipsing systems, where over 30% of the sources with primary and secondary eclipses show a secular change in their intereclipse timings and relative eclipse depths over a multiyear timescale, likely due to orbital precession. The orbital parameters of the population are estimated by fitting a heartbeat model to their phase curves and Gaia magnitudes, where the model accounts for ellipsoidal variability, Doppler beaming, reflection effects, and eclipses. We construct the sample’s period–eccentricity distribution and find an eccentricity cutoff (where e → 0) at a period of 1.7 days. Additionally, we measure the periastron advance rate for 12 of the precessing sources and find that they all exhibit prograde apsidal precession, which is as high as 9° yr ^−1 for one of the systems. Using the inferred stellar parameters, we estimate the general relativistic precession rate of the argument of periastron for the population and expect over 30 systems to show a precession in excess of 0.3° yr ^−1 .

Keywords

• Eclipsing binary stars
• Close binary stars