Mode identification in rapidly rotating stars from BRITE data

TL;DR

This paper advances mode identification in rapidly rotating stars by developing 2D non-adiabatic pulsation models using ESTER, and applies these to BRITE multi-colour photometry to improve observational mode classification.

Contribution

It introduces the first self-consistent 2D non-adiabatic pulsation predictions for rapidly rotating stars and applies them to BRITE data for mode identification.

Findings

Developed 2D non-adiabatic pulsation models for rapid rotators

Predicted amplitude ratios and phase differences for BRITE bands

Enhanced prospects for mode identification in rapid rotators

Abstract

Apart from recent progress in Gamma Dor stars, identifying modes in rapidly rotating stars is a formidable challenge due to the lack of simple, easily identifiable frequency patterns. As a result, it is necessary to look to observational methods for identifying modes. Two popular techniques are spectroscopic mode identification based on line profile variations (LPVs) and photometric mode identification based on amplitude ratios and phase differences between multiple photometric bands. In this respect, the BRITE constellation is particularly interesting as it provides space-based multi-colour photometry. The present contribution describes the latest developments in obtaining theoretical predictions for amplitude ratios and phase differences for pulsation modes in rapidly rotating stars. These developments are based on full 2D non-adiabatic pulsation calculations, using models from the ESTER code, the only code to treat in a self-consistent way the thermal equilibrium of rapidly rotating stars. These predictions are then specifically applied to the BRITE photometric bands to explore the prospects of identifying modes based on BRITE observations.