Internal mixing of rotating stars inferred from dipole gravity modes

TL;DR

This study uses dipole gravity modes to infer internal mixing profiles in 26 rotating stars, revealing diverse mixing levels and supporting stratified models for better asteroseismic accuracy, thus informing stellar evolution theories.

Contribution

First observationally constrained internal mixing profiles in rotating stars using gravity modes, enhancing understanding of stellar interior processes.

Findings

Wide range of internal mixing levels observed.

Stratified mixing profiles improve asteroseismic modeling.

Results guide hydrodynamical simulations of stellar interiors.

Abstract

During most of their life, stars fuse hydrogen into helium in their cores. The mixing of chemical elements in the radiative envelope of stars with a convective core is able to replenish the core with extra fuel. If effective, such deep mixing allows stars to live longer and change their evolutionary path. Yet localized observations to constrain internal mixing are absent so far. Gravity modes probe the deep stellar interior near the convective core and allow us to calibrate internal mixing processes. Here we provide core-to-surface mixing profiles inferred from observed dipole gravity modes in 26 rotating stars with masses between 3 and 10 solar masses. We find a wide range of internal mixing levels across the sample. Stellar models with stratified mixing profiles in the envelope reveal the best asteroseismic performance. Our results provide observational guidance for three-dimensional hydrodynamical simulations of transport processes in the deep interiors of stars.