Pulsations of rapidly rotating stars: II. Realistic modelling for intermediate-mass stars

TL;DR

This paper develops realistic 2D models of rapidly rotating stars to analyze their complex pulsation spectra, including mixed modes, aiding interpretation of asteroseismic data from missions like CoRoT and Kepler.

Contribution

It introduces a self-consistent method to create 2D stellar models and studies their pulsation spectra using a non-perturbative oscillation code, including mixed modes in rapid rotators.

Findings

Confirmed regularity of island mode spectra and established new quantum numbers.

First calculation of mixed gravito-acoustic modes in rapidly rotating stellar models.

Demonstrated the effectiveness of the 2D modeling approach for interpreting asteroseismic data.

Abstract

Very high precision seismic space missions such as CoRoT and Kepler provide the means for testing the modelling of transport processes in stellar interiors. For some stars, such as $\delta$ Scuti $\gamma$ Doradus and Be stars, for instance, the observed pulsation spectra are modified by rotation to such an extent that it prevents any fruitful interpretation. Our aim is to characterise acoustic pulsation spectra of realistic stellar models in order to be able to interpret asteroseismic data from such stars. The 2-dimensional oscillation code ACOR, which treats rotation in a non-perturbative manner, is used to study pulsation spectra of highly distorted evolved models of stars. 2D models of stars are obtained by a self-consistent method which distorts spherically averaged stellar models a posteriori, at any stage of evolution, and for any type of rotation law. Four types of modes are calculated in a very dense frequency spectrum, among which are island modes. The regularity of the island modes spectrum is confirmed and yields a new set of quantum numbers, with which an \'echelle diagram can be built. Mixed gravito-acoustic modes are calculated in rapidly rotating models for the first time.