Constraining core-to-envelope differential rotation in gamma-doradus stars from inertial dips properties

TL;DR

This study investigates how differential rotation between the core and envelope of gamma-Doradus stars affects inertial dip features in their pulsation patterns, providing insights into stellar internal dynamics.

Contribution

It introduces a bi-layer rotation model and derives a modified Lorentzian profile to analyze inertial dips, advancing understanding of core-envelope differential rotation effects.

Findings

Inertial dips are sensitive to core-to-envelope differential rotation.

The modified Lorentzian profile better fits inertial dip observations under differential rotation.

Core rotation influences the shape and location of inertial dips.

Abstract

The presence of dips in the gravito-inertial modes period-spacing pattern of gamma-Dor stars is now well established by recent asteroseismic studies. Such Lorentzian-shaped inertial dips arise from the interaction of gravito-inertial modes propagating in the radiative envelope of intermediate-mass main sequence stars with pure inertial modes that propagate in their convective core. We aim to investigate the signature of a differential rotation between the convective core and the near-core region inside gamma-Dor stars from the inertial dip properties. We first describe the bi-layer rotation profile we use and the approximations we adopt to maintain the analyticity of our study. We then describe our results on the inertial dip formation, location, and shape. We derive a modified Lorentzian profile and we compare it to the previously obtained results in the solid-body rotation case. This work highlights the inertial dips' probing power of the convective core rotation, an important observable in the context of the understanding of the angular momentum transport and chemicals mixing inside stars.