Sound-speed inversion of the Sun using a nonlocal statistical convection theory

TL;DR

This paper improves the solar model's accuracy in sound-speed predictions by applying a nonlocal convection theory, addressing discrepancies found with traditional local models.

Contribution

It introduces a self-consistent nonlocal convection model for the Sun, reducing sound-speed discrepancies compared to standard models.

Findings

Significant reduction in sound-speed discrepancy

Smooth transition from convective to radiative zones

Convective flux changes sign at convection zone boundaries

Abstract

Helioseismic inversions reveal a major discrepancy in sound speed between the Sun and the standard solar model just below the base of solar convection zone. We demonstrate that this discrepancy is caused by the inherent shortcomings of the local mixing-length theory adopted in the standard solar model. Using a self-consistent nonlocal convection theory, we construct an envelope model of the Sun for sound-speed inversion. Our solar model has a very smooth transition from the convective envelope to the radiative interior; and the convective energy flux changes sign crossing the boundaries of the convection zone. It shows evident improvement over the standard solar model, with a significant reduction in the discrepancy in sound speed between the Sun and local convection models.