Coupling 1D stellar evolution with 3D-hydrodynamical simulations on-the-fly I: A New Standard Solar Model

TL;DR

This paper introduces a novel method that integrates 3D stellar envelope simulations into 1D stellar evolution models, significantly improving the accuracy of surface layer structures and oscillation frequency predictions for the Sun.

Contribution

A new on-the-fly coupling technique that imposes 3D simulation structures during stellar evolution, enhancing model realism and helioseismic agreement.

Findings

Surface layer structures closely match 3D simulations for the Sun.

Model frequencies show reduced discrepancies with observed p-modes.

Method provides a continuous transition from interior to surface layers.

Abstract

Standard 1D stellar evolution models do not correctly reproduce the structure of the outermost layers of stars with convective envelopes. This has been a long-standing problem in stellar modelling affecting both the predicted evolutionary paths and the attributed oscillation frequencies, and indirectly biasing numerous quantities derived from stellar evolution calculations. We present a novel method that mostly eliminates these structural defects by appending mean 3D simulations of stellar envelopes. In contrast to previous attempts we impose the complete structure derived from 3D simulations at each time step during the entire evolution. For this purpose, we interpolate in grids of pre-computed 3D simulations and use the resulting structure as boundary conditions, in order to solve the stellar structure equations for the 1D interior at each time step. Our method provides a continuous transition in many quantities from the interior to the imposed interpolated 3D surface layers. We present a solar calibration model and show that the obtained structure of the surface layers reliably mimics that of the underlying 3D simulations for the present Sun. Moreover, we perform a helioseismic analysis, showing that our method mostly eliminates the structural contribution to the discrepancy between model frequencies and observed p-mode frequencies.