Discriminating between overshooting and rotational mixing in massive stars: any help from asteroseismology?

TL;DR

This paper explores how asteroseismology can differentiate between overshooting and rotational mixing in massive stars by analyzing gravity mode spectra, revealing distinct signatures of each process.

Contribution

It demonstrates that rotationally induced mixing leaves a detectable signature in gravity mode frequencies, enabling discrimination from overshooting effects in main-sequence B-type stars.

Findings

Rotational mixing significantly perturbs gravity mode spectra.

Gravity mode signatures can distinguish between overshooting and rotational mixing.

Applicable to Slowly Pulsating B stars and beta Cephei stars.

Abstract

Chemical turbulent mixing induced by rotation can affect the internal distribution of mu near the energy-generating core of main-sequence stars, having an effect on the evolutionary tracks similar to that of overshooting. However, this mixing also leads to a smoother chemical composition profile near the edge of the convective core, which is reflected in the behaviour of the buoyancy frequency and, therefore, in the frequencies of gravity modes. We show that for rotational velocities typical of main-sequence B-type pulsating stars, the signature of a rotationally induced mixing significantly perturbs the spectrum of gravity modes and mixed modes, and can be distinguished from that of overshooting. The cases of high-order gravity modes in Slowly Pulsating B stars and of low-order g modes and mixed modes in beta Cephei stars are discussed.