Orbital and physical parameters of the close binary system GJ 9830 (HIP 116259)

Abstract

We present the complete set of physical and geometrical parameters of the visual close binary system GJ 9830 for the first time by applying Al-Wardat’s complex method. This method combines magnitude difference from speckle interferometry, synthetic spectral energy distributions of the binary components which are constructed based on grids of Kurucz blanketed models (ATLAS9), and the orbital solution using Tokovinin’s dynamical method to estimate the parameters of individual components. The analysis of the system by employing synthetic photometry resulted in the following set of parameters: Teff = 6220 ± 100 K, log g = 4.30 ± 0.12, R = 1.10 ± 0.08 R⊙for the primary component and Teff = 4870 ± 100 K, log g = 4.60 ± 0.11, R = 0.709 ± 0.07 R⊙for the secondary component. The recently published dynamical parallax from the Gaia space mission was used to calculate the total mass of the binary system as 1.75 ± 0.06 ℳ⊙, which coincides with those estimated using Al-Wardat’s method as ℳA = 1.18±0.10 ℳ⊙, ℳB = 0.75±0.08 ℳ⊙. The analysis of the system reveals that both components are characteristic of main sequence stars and have an age of around 1.4±0.50 Gyr. The evolutionary tracks and isochrones of the system’s components are discussed, and the fragmentation process is suggested as the most likely process for the formation of the system.