Two newly identified eclipsing binaries in open cluster NGC 3532

Abstract

We present light curve analyses of two newly identified detached eclipsing binaries, HD 96609 and HD 303734, in the region of the richly populated open cluster NGC 3532. HD 96609 is composed of two main sequence stars (B9-A0V + A2V) with masses and radii of $M_{1}=2.66\pm0.02$$M_{\odot}$, $M_{2}=1.84\pm0.01$$M_{\odot}$, $R_{1}=2.740\pm0.006$$R_{\odot}$, $R_{2}=1.697\pm0.005$$R_{\odot}$. The positions of the components on $log~M-log~R$ plane suggests log(age/yr) 8.55, corresponding $350\pm40$ Myr of age, which agrees with the $300\pm100$ Myr age of NGC 3532 estimated in previous studies. We find the distance of HD 96609 as $460\pm17$ pc, which is consistent with the $484^{+35}_{-30}$ pc distance of NGC 3532, estimated from GAIA parallaxes. HD 303734 is an interesting totally eclipsing binary with a quite shallow secondary eclipse. Using photometric properties of the system in conjunction with theoretical calibrations, we estimate that HD 303734 consists of A6V + K3V components. HD 96609 and HD 303734 are the second and third eclipsing binaries discovered in the region of NGC 3532, after the first one, GV Car.