Unexpected stratification in the equivalent-duration distributions of flare stars

ABSTRACT In this study, the results obtained from the statistical models of flares observed with ground-based telescopes and TESS observations for the UV Ceti-type stars AD Leo and V1005 Ori are presented. The distribution of flare equivalent duration versus total flare duration for the flares of both stars, observed with different telescopes, has been modelled using the one-phase exponential association (OPEA) model. Although no bifurcation was observed in the models derived with the flare data of V1005 Ori, the OPEA model exhibited bifurcation in almost all observation data of AD Leo. While many similar studies have shown that such models derived for a star do not vary over time and exhibit a single distribution in the same observation season, the stratification in AD Leo’s distributions and consequently in its model is an unexpected result.