Stellar models with calibrated convection and temperature stratification from 3D hydrodynamics simulations

TL;DR

This paper integrates detailed 3D hydrodynamics simulation results into stellar evolution models to improve the treatment of outer stellar layers, leading to more accurate temperature stratification and convection calibration.

Contribution

It introduces a method to incorporate 3D simulation-based temperature stratification and variable mixing-length parameters into stellar evolution codes, including a publicly available MESA module.

Findings

Minimal impact on overall stellar evolution and structure

Effective temperature changes up to 30 K in specific phases

First asteroseismic analysis using 3D-calibrated models

Abstract

Stellar evolution codes play a major role in present-day astrophysics, yet they share common simplifications related to the outer layers of stars. We seek to improve on this by the use of results from realistic and highly detailed 3D hydrodynamics simulations of stellar convection. We implement a temperature stratification extracted directly from the 3D simulations into two stellar evolution codes to replace the simplified atmosphere normally used. Our implementation also contains a non-constant mixing-length parameter, which varies as a function of the stellar surface gravity and temperature -- also derived from the 3D simulations. We give a detailed account of our fully consistent implementation and compare to earlier works, and also provide a freely available MESA-module. The evolution of low-mass stars with different masses is investigated, and we present for the first time an asteroseismic analysis of a standard solar model utilising calibrated convection and temperature stratification from 3D simulations. We show that the inclusion of 3D results have an almost insignificant impact on the evolution and structure of stellar models -- the largest effect are changes in effective temperature of order 30 K seen in the pre-main sequence and in the red-giant branch. However, this work provides the first step for producing self-consistent evolutionary calculations using fully incorporated 3D atmospheres from on-the-fly interpolation in grids of simulations.