Semiconvective Mixing in Low-Mass Stars

TL;DR

This paper investigates the impact of semiconvective mixing on the internal structure and observable properties of low-mass stars with convective cores, using various modeling prescriptions.

Contribution

It introduces new models exploring different semiconvective mixing prescriptions and boundary definitions in low-mass stars, highlighting their effects on stellar evolution.

Findings

Semiconvective mixing influences core structure and evolution.

Different prescriptions lead to observable differences in stellar properties.

Models show semiconvection's role in low-mass star evolution.

Abstract

Mixing processes such as convection, overshooting and rotational mixing have long been known to affect the evolutionary properties of low-mass stars. While modeling a 1.2 Msun star, we encountered a semiconvective region outside the fully convective core, reminiscent of the well-known situation for massive stars. In this study we focus on low-mass stars presenting convective cores and, by applying different prescriptions for the determination of the convective boundaries and using different mixing descriptions for the dynamical processes in the core, we look for the effects of semiconvective mixing in the interior structure of the stars and its observable quantities. With this purpose, we have constructed different sets of evolutionary models using a stellar evolution code (GARSTEC), and analyzed the models looking for imprints of these processes.