Addressing the acoustic tachocline anomaly and the lithium depletion problem at the same time

TL;DR

This paper investigates whether diffusive overshooting in solar models can simultaneously explain the Sun's lithium depletion and sound speed profile, finding it insufficient to solve both issues at once.

Contribution

The study analyzes four diffusive overshooting parametrizations and demonstrates their limitations in addressing both solar lithium depletion and sound speed discrepancies simultaneously.

Findings

Overshooting models recover lithium depletion when suppressed early on.

Parametrizations improve the sound speed profile.

No model simultaneously solves both problems.

Abstract

Current standard solar models neither account properly for the photospheric lithium abundance nor reproduce the inferred solar sound speed profile. Diffusive overshooting at the base of the solar convective envelope has previously been shown to solve either of these model inadequacies. In this paper, we present an analysis of solar models with four different parametrizations of diffusive overshooting. We find that these models are able to recover the correct lithium depletion, regardless of the parametrization, if overshooting is suppressed, during the early evolutionary stages. Further, parametrizations of diffusive overshooting have been shown to improve the inferred sound speed profile. However, none of the presented models are able to simultaneously solve both model inadequacies, showing that diffusive overshooting on its own is deficient to account for observations.