Bayesian inference of stellar parameters based on 1D stellar models coupled with 3D envelopes

TL;DR

This paper demonstrates that incorporating 3D hydrodynamic simulations into 1D stellar models reduces parameter degeneracies, leading to more accurate and robust estimates of stellar properties for main-sequence stars.

Contribution

It introduces a Bayesian inference approach using 3D simulation-informed 1D models to improve stellar parameter estimation and reduce reliance on the mixing length parameter.

Findings

3D simulations make 1D stellar structures nearly insensitive to the mixing length parameter

Inclusion of 3D simulations reduces degeneracy between stellar parameters

More realistic models improve robustness of stellar parameter estimates

Abstract

Stellar models utilising one-dimensional (1D), heuristic theories of convection fail to adequately describe the energy transport in superadiabatic layers. The improper modelling leads to well-known discrepancies between observed and predicted oscillation frequencies for stars with convective envelopes. Recently, three-dimensional (3D) hydrodynamic simulations of stellar envelopes have been shown to facilitate a realistic depiction of superadiabatic convection in 1D stellar models. The resulting structural changes of the boundary layers have been demonstrated to impact not only the predicted oscillation spectra but evolution tracks as well. In this paper, we quantify the consequences that the change in boundary conditions has for stellar parameter estimates of main-sequence stars. For this purpose, we investigate two benchmark stars, Alpha Centauri A and B, using Bayesian inference. We show that the improved treatment of turbulent convection makes the obtained 1D stellar structures nearly insensitive to the mixing length parameter. By using 3D simulations in 1D stellar models, we hence overcome the degeneracy between the mixing length parameter and other stellar parameters. By lifting this degeneracy, the inclusion of 3D simulations has the potential to yield more robust parameter estimates. In this way, a more realistic depiction of superadiabatic convection has important implications for any field that relies on stellar models, including the study of the chemical evolution of the Milky Way Galaxy and exoplanet research.