Coupling 1D stellar evolution with 3D-hydrodynamical simulations on-the-fly II: Stellar Evolution and Asteroseismic Applications

TL;DR

This paper advances stellar modeling by integrating 3D hydrodynamical simulations on-the-fly, improving outer layer accuracy and asteroseismic predictions across different star types, including red giants.

Contribution

It extends a novel on-the-fly integration method to multiple simulation grids and applies it across the HR diagram, enhancing stellar models and asteroseismic analysis.

Findings

Improved outer stratification and oscillation frequencies in solar models.

Red-giant branch shifted about 40 K to higher temperatures.

Significant reduction of the asteroseismic surface term in selected stars.

Abstract

Models of stellar structure and evolution are an indispensable tool in astrophysics, yet they are known to incorrectly reproduce the outer convective layers of stars. In the first paper of this series, we presented a novel procedure to include the mean structure of 3D hydrodynamical simulations on-the-fly in stellar models, and found it to significantly improve the outer stratification and oscillation frequencies of a standard solar model. In the present work, we extend the analysis of the method; specifically how the transition point between envelope and interior affects the models. We confirm the versatility of our method by successfully repeating the entire procedure for a different grid of 3D hydro-simulations. Furthermore, the applicability of the procedure was investigated across the HR diagram and an accuracy comparable to the solar case was found. Moreover, we explored the implications on stellar evolution and find that the red-giant branch is shifted about 40 K to higher effective temperatures. Finally, we present for the first time an asteroseismic analysis based on stellar models fully utilising the stratification of 3D simulations on-the-fly. These new models significantly reduce the asteroseismic surface term for the two selected stars in the Kepler field. We extend the analysis to red giants and characterise the shape of the surface effect in this regime. Lastly, we stress that the interpolation required by our method would benefit from new 3D simulations, resulting in a finer sampling of the grid.