Classifying Be Star Variability with TESS I.

Among the Be stars with brightening events that are characteristic of mass ejection episodes (18% of the full sample, or 31% of early-type stars), all have at least one frequency group, and the majority of these (83%) show a concurrent temporary amplitude enhancement in one or more frequency groups. About one-third (34%) of the sample is dominated by longer-term trends (timescales >2day). Low-frequency stochastic signals are prominent in about 25% of the sample, with varying degrees of intensity.

Higher-frequency signals (6<f<15/day) are sometimes seen (in 15% of the sample) and in most cases likely reflect p-mode pulsation. In rare cases (~3%), even higher frequencies beyond the traditional p-mode regime (f>15/day) are observed.