Flares & flaring stars from TESS & machine learning

We find strong correlations of total flare energy and flare amplitude with color, in agreement with previous studies. Flare frequency distributions are analyzed, refining power-law slopes for flare behavior with frequency uncertainties due to the detection incompleteness of low-amplitude events. We determine rotation periods for ~120,000 stars thus yielding the relationship between rotation period and flare activity.

We find that the transition in rotation period between the saturated and unsaturated regimes in flare energy coincides with the same transition in rotation period separating the saturated and unsaturated levels in coronal X-ray emission. We find that X-ray emission increases more rapidly with flare luminosity in earlier-type and unsaturated stars, indicating more efficient coronal heating in these objects. Additionally, we detect flares in white dwarfs and hot subdwarfs, which likely arise from unresolved low-mass companions.