Observed Rate Variations in Superflaring G-type Stars

Abstract

Flare occurrence on the Sun is highly variable, exhibiting both short-term variation due to the emergence and evolution of active regions, and long-term variation from the solar cycle. On solar-like stars, more energetic stellar flares (superflares) have been observed, and it is of interest to determine whether the observed rates of superflare occurrence exhibit similar variability to solar flares. We analyze 274 G-type stars using data from the Transiting Exoplanet Survey Satellite and identify seven stars which exhibit statistically significant changes in the rate of superflare occurrence by fitting a piecewise constant-rate model with the Bayesian blocks algorithm. We investigate the properties of these stars and their flaring rates, and discuss the possible reasons for the low number of stars with detectable rate variation.