Towards Understanding the Nature of Young Detached Binary System HD 350731

TL;DR

This study provides detailed physical and orbital parameters of the young detached binary HD 350731, including masses, radii, temperatures, and velocities, enhancing understanding of early-type binary systems.

Contribution

First simultaneous solution of light and radial velocity curves for HD 350731, determining accurate absolute parameters and evolutionary status of the system.

Findings

HD 350731 consists of two B8V-type stars with well-measured masses and radii.

The components' temperatures and velocities suggest pseudo-synchronous rotation.

The system is approximately 120 million years old and belongs to the young thin-disc population.

Abstract

The young binary system HD 350731 is a noteworthy laboratory for studying early-type binaries with similar components. We present here the analysis of differential multi-color photometric and spectroscopic observations for the double-lined detached system. Accurate absolute parameters were determined from the simultaneous solution of light and radial velocity curves for the first time. HD 350731 consists of two B8V-type components having masses and radii respectively of $M_{1}=2.91\pm0.13$ M$_{\odot}$, $M_{2}=2.80\pm0.14$ M$_{\odot}$, $R_{1}= 2.11 \pm0.05$ R$_{\odot}$ and $R_{2}=2.07\pm0.05$ R$_{\odot}$. The effective temperatures were determined based on analysis of disentangled spectra of the components and derived to be $12000\pm250$ K and $11830\pm300$ K for the primary and secondary components, respectively. The measured projected rotational velocities, 69.2$\pm$1.5 km s$^{-1}$ for primary and 70.1$\pm$1.7 km s$^{-1}$ for secondary, were found closer to the pseudo-synchronous velocities of the components. Comparison with evolutionary models suggests an age of 120$\pm$35 Myr. Kinematic analysis of the unevolved binary system HD 350731 revealed that it belongs to the young thin-disc population of the Galaxy.