TESS photometry of classical Be stars: rapid rotation, pulsation, and links to mass ejection

Classical Be stars are near-critical rotators which occasionally eject mass and angular momentum to form circumstellar 'decretion' disks. Space photometry has revealed that Be stars are pulsators as a rule, and evidence is mounting that pulsation plays a role in the mass ejection mechanism. This poster will provide a summary of a study of the TESS light curves for ~500 Be stars. Virtually all Be stars are variable, with the vast majority showing `frequency groups' (which represent multi-mode pulsation). About 20% of the sample shows brightening events that reflect mass ejection episodes, often with associated enhancements in the strength of the frequency groups. In some stars, there is evidence of non-linear coupling of individual pulsation modes which can control the timing of mass outbursts. Time-series spectroscopy simultaneous with the TESS observations for selected targets provides crucial information for interpreting the photometric variability. Correlations between different variability patterns are studied to better understand the overall behavior of the Be star population.