Properties of Galactic B[e] Supergiants. X. Refined Orbit and Fundamental Parameters of the HD 327083 Binary System

Abstract

HD 327083 is a binary system that consists of two supergiant components and exhibits the B[e] phenomenon. In this paper, we report the determination of a new set of the system’s fundamental parameters using a combination of photometric and spectroscopic data as well as the Gaia EDR3 distance. We found that the orbital period of the system is 107.68 ± 0.02 days. The spectral line content implies the effective temperatures of ≈7000 K and 25,400 ± 1400 K, while the photometric variations are consistent with the radii of ≈106 R _⊙ and ≈10 R _⊙ for the cool and hot components, respectively. The absorption lines of the cool component show a radial velocity semiamplitude of 48.3 ± 1.7 km s ^−1 , similar to that of the emission lines that originate around the hot component. The inclination of the system to the line of sight is ${47}_{-20}^{+17}$ °. Modeling of the system's evolutionary history suggests that the components have masses of ∼12.5 M _⊙ and currently undergo mass transfer between them. This configuration, which takes in heating of the surface of the cool component by the radiation from the hot one, can reproduce the photometric and spectroscopic data and is in agreement with previous infrared observations of the circumbinary disk. The results of this study further confirm the hypothesis that the reason for the presence of the B[e] phenomenon in most objects is a consequence of the evolution of various binary systems.

Keywords

• A stars
• Binary stars
• Emission line stars