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

## TL;DR

This study determines the physical and orbital parameters of the close binary system GJ 9830 using a combined method involving synthetic spectral modeling and orbital analysis, providing detailed stellar characteristics and evolutionary insights.

## Contribution

First comprehensive analysis of GJ 9830's physical and orbital parameters using Al-Wardat's method combined with Gaia data, revealing stellar properties and formation history.

## Key findings

- Both stars are main sequence with ages around 1.4 Gyr.
- Total mass of the system is approximately 1.75 solar masses.
- Primary and secondary masses are about 1.18 and 0.75 solar masses, respectively.

## Abstract

We present the complete set of physical and geometrical parameters of the visual close binary system GJ\,9830 for the first time by using Al-Wardat's complex method. This method combines magnitude difference from speckle interferometry, synthetic spectral energy distributions of the binary components which are constructed depending on grids of Kurucz blanketed models (Atlas9), along with the orbital solution by using Tokovinin's dynamical method to estimate the parameters of the individual components. The analysis of the system by using synthetic photometry resulted in the following set of parameters: $T_{\rm eff.}=6220\pm 100$ \,K, $\rm log~g=4.30\pm 0.12$, $R=1.10\pm0.08\,R_\odot$ for the primary component and $T_{\rm eff.}=4870\pm 100$\,K, $\rm log~g=4.60\pm 0.11$, $R=0.709\pm0.07\,R_\odot$ for the secondary component. The recently published dynamical parallax from \textit{Gaia} space mission was used to calculate the total mass of the binary system as $1.75\pm0.06\, \mathcal{M}_\odot$ which coincides with those estimated by using Al-Wardat's method as $ \mathcal{M}^{A}=1.18\pm0.10\, \mathcal{M}_\odot$, $ \mathcal{M}^{B}=0.75\pm0.08\, \mathcal{M}_\odot$. The analysis of the system reveals that both components belong to main sequence stars with an age around $1.4\pm0.50$\,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.