Astrophysical Properties of the Sirius Binary System Modeled with MESA

TL;DR

This study models the Sirius binary system's evolution using MESA, deriving stellar parameters and age, and compares results with other stellar evolution codes to understand its past and current characteristics.

Contribution

First detailed MESA-based evolutionary model of Sirius system incorporating observational data, providing new estimates of progenitor mass, age, and metallicity.

Findings

Progenitor mass of Sirius B is approximately 6.0 solar masses.

System age estimated at around 204 million years.

Results are consistent with a non-interacting evolutionary history.

Abstract

Sirius is the brightest star in the night sky and, despite its proximity, this binary system still imposes intriguing questions about its current characteristics and past evolution. Bond et. al. (arXiv:1703.10625) published decades of astrometric measurements of the Sirius system, determining the dynamical masses for Sirius A and B, and the orbital period. We have used these determinations, combined with photometric determinations for luminosity and spectroscopic determinations of effective temperature ($T_{eff}$) and metallicity, to model the evolution of the Sirius system using MESA (Modules for Experiments in Stellar Astrophysics). We have constructed a model grid calculated especially for this system and were able to obtain, for Sirius B, a progenitor mass of $6.0 \pm 0.6 M_{\odot}$, yielding a white dwarf mass of $1.015 \pm 0.189 M_{\odot}$. Our best determination for age of the system is $203.6 \pm 45$ Myr with a metallicity of 0.0124. We have compared our best fit models with the ones computed using TYCHO, YREC, and PARSEC, establishing external uncertainties. Our results are consistent with the observations and support a non-interacting past.