Evidence for Sympathetic Flaring in TESS Data

Abstract Most flares on the Sun occur at random, but there is a small percentage of “sympathetic flaring”—the triggering of one flare by another. Previously there had been no widespread confirmation of sympathetic flares on other stars. In this work, we developed a new flare detection algorithm that is sensitive to closely separated and overlapping stellar flares. We applied it to the Transiting Exoplanet Survey Satellite (TESS) data and discovered ∼220,000 flares on ∼16,000 stars, the majority of which are M dwarfs. The wait time distribution between flares demonstrates an excess of closely separated flares relative to expectations from a Poisson process. We attribute this to sympathetic flares, occurring at a rate of between 4% and 9%, which matches the rate seen on the Sun. Our result is the first statistically robust detection of sympathetic flares on other stars, demonstrating a commonality between the Sun and low-mass stars.