Regular modes in rotating stars

TL;DR

This paper develops an asymptotic theory for regular acoustic modes in rotating stars using ray dynamics, enabling better interpretation of observational data and insights into stellar interiors.

Contribution

It introduces a non-perturbative asymptotic framework for understanding regular modes in rotating stars based on acoustic ray dynamics, validated against numerical simulations.

Findings

Accurately describes frequency and amplitude distributions of modes across rotation rates

Spectra characterized by two quantum numbers, aiding mode identification

Potential to extract stellar interior information from observed spectra

Abstract

Despite more and more observational data, stellar acoustic oscillation modes are not well understood as soon as rotation cannot be treated perturbatively. In a way similar to semiclassical theory in quantum physics, we use acoustic ray dynamics to build an asymptotic theory for the subset of regular modes which are the easiest to observe and identify. Comparisons with 2D numerical simulations of oscillations in polytropic stars show that both the frequency and amplitude distributions of these modes can accurately be described by an asymptotic theory for almost all rotation rates. The spectra are mainly characterized by two quantum numbers; their extraction from observed spectra should enable one to obtain information about stellar interiors.