An Analysis of the Eclipsing Binaries HD 71636, V1022 Cassiopeiae, and OT Andromedae

Abstract

Abstract We have obtained high-dispersion spectroscopy and BV photometry of two F-type eclipsing binaries, HD 71636 and V1022 Cas, plus the A-type system OT And. Transiting Exoplanet Survey Satellite measurements for each system have also been incorporated. The photometry of HD 71636 enables a more consistent picture of this 5.01331 days, circular-orbit system to emerge. The F2 V primary has a mass of 1.506 ± 0.002 M ☉ and a radius of 1.583 ± 0.024 R ☉. The mass of the F5 V secondary is 1.282 ± 0.002 M ☉, and its radius is 1.314 ± 0.030 R ☉. Comparison with evolutionary models of the Modules for Experiments in Stellar Astrophysics (MESA) series results in a good fit for a composition of [Fe/H] = 0.12 and an age of 0.9 Gyr. For the F6 V stars of V1022 Cas, our analysis produces a period of 12.15616 days and an eccentricity of 0.312. The two components have nearly equal masses of 1.626 ± 0.001 M ☉ and 1.607 ± 0.001 M ☉. The radii of the primary and secondary are 2.570 ± 0.021 R ☉ and 2.445 ± 0.022 R ☉, respectively. Comparison with the MESA evolutionary models results in [Fe/H] = 0.08 and an age of 1.87 Gyr. OT And consists of a pair of similar mid-A stars that have an orbital period of 20.85292 days and an eccentricity of 0.215. The primary has a mass of 2.253 ± 0.014 M ☉ and a radius of 3.167 ± 0.013 R ☉. The corresponding parameters for the secondary are 2.147 ± 0.011 M ☉ and 2.649 ± 0.015 R ☉, respectively. The MESA series models produce a best fit for this system with [Fe/H] = 0.10 and an age of 0.675 Gyr. The total apsidal motion in both eccentric systems is less than 1.°5 century−1.