2015AJ....150...55S

The young binary system HD 350731 is a noteworthy laboratory for studying early-type binaries with similar components. We present here an analysis of differential multi-color photometric and spectroscopic observations of the double-lined detached system. Accurate absolute parameters were determined for the first time from a simultaneous solution of the light and radial velocity curves. HD 350731 consists of two B8V-type components with masses and radii, respectively, of M₁ = 2.91 ± 0.13M_☉, M₂ = 2.80 ± 0.14M_☉, R₁ = 2.11 ± 0.05R_☉ and R₂ = 2.07 ± 0.05 R☉_. The effective temperatures were determined based on analysis of disentangled spectra of the components and were derived to be 12,000±250 and 11,830±300 K for the primary and secondary components, respectively. The measured projected rotational velocities, 69.2±1.5 km/s for the primary and 70.1±1.7 km/s for the secondary, were found to be closer to the pseudo-synchronous velocities of the components. Comparison with evolutionary models suggests an age of 120±35 Myr. Kinematic analysis of the unevolved binary system HD 350731 revealed that it belongs to the young thin-disk population of the Galaxy.