TOWARD UNDERSTANDING THE NATURE OF THE YOUNG DETACHED BINARY SYSTEM HD 350731

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 , , , and . 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−1 for the primary and 70.1 ± 1.7 km s−1 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.