Non-adiabatic oscillations of fast-rotating stars: the example of Rasalhague

TL;DR

This study models the complex oscillation spectra of fast-rotating early-type stars like Rasalhague using 2D structure and oscillation codes, aiming to improve mode identification despite current challenges.

Contribution

It applies advanced 2D modeling and non-adiabatic oscillation calculations to analyze fast-rotating stars, providing early promising results for mode identification.

Findings

Complex oscillation spectra obtained

Diagnostic tools used for mode identification

Initial promising results despite challenges

Abstract

Early-type stars generally tend to be fast rotators. In these stars, mode identification is very challenging as the effects of rotation are not well known. We consider here the example of $\alpha$ Ophiuchi, for which dozens of oscillation frequencies have been measured. We model the star using the two-dimensional structure code ESTER, and we compute both adiabatic and non-adiabatic oscillations using the TOP code. Both calculations yield very complex spectra, and we used various diagnostic tools to try and identify the observed pulsations. While we have not reached a satisfactory mode-to-mode identification, this paper presents promising early results.