Main Sequence Star Super-flare Frequency based on Entire Kepler Data

Abstract

Abstract We wrote and used an automated flare detection Python script to search for super-flares on main sequence stars of types A, F, G, K and M in Kepler’s long-cadence data from Q0 to Q17. We studied the statistical properties of the occurrence rate of super-flares. For the G-type data set, we compared our results with the previous results of Okamoto et al. by splitting the data set into four rotational bands. We found similar power-law indices for the flare frequency distribution. Hence, we show that inclusion of a high-pass filter, sample biases, gyrochronology and completeness of flare detection is of no significance, as our results are similar to those of Okamoto et al. We estimated that a super-flare on G-type dwarfs with energy of 1035 erg occurs on a star once every 4360 yr. We found 4637 super-flares on 1896 G-type dwarfs. Moreover, we identified 321, 1125, 4538 and 5445 super-flares on 136, 522, 770 and 312 dwarfs of types A, F, K and M, respectively. We ascertained that the occurrence rate (dN/dE) of super-flares versus flare energy, E, shows a power-law distribution with dN / dE ∝ E − α , where α ≃ 2.0 to 2.1 for the spectral types from F-type to M-type stars. In contrast, the obtained α ≃ 1.3 for A-type stars suggests that the flare conditions differ from those of the other spectral-type stars. We note an increase in flare incidence rate in F-type to M-type stars and a decrease in A-type to F-type stars.