Flare catalog through LC data of Kepler DR25

The activity-rotation relation is consistent with previous studies at low temperature bands, whereas it becomes dispersive with increasing temperature. Combined with the Gyrochronology, we find that the mixing of stars of two different dynamos gives rise to the dispersion. We thereby propose a scenario on understanding the activity-rotation relation across the Hertzsprung-Russell diagram.

Based on the scenario and the correspondence of dynamo with regard to activity and rotation, we suggest a new expression on the activity-rotation relation, in which the segmentation is on the basis of the dynamo rather than the rotation period. The rotation distribution of flare stars shows that about 70% of flare stars rotate faster than 10 days and the rate approaches 95% at 30 days. Based on the incidence and the rotation distribution of flare stars, we estimate that a superflare with energy ~10^34^erg occurs on the Sun at least once in 5500yr.