Large-sample Statistics of Flares in Eclipsing Binaries Based on TESS and Gaia Data

Abstract

Stellar flares are one of the most prominent phenomena on the surface of stars, and they can have a profound impact on the space environment, constrain the stellar magnetic evolution theory, and support livable exoplanet surveys. Limited by observations, previous research was aimed at individual flaring stars, especially those with superflares. Here we searched for flares in a large-scale eclipsing-binary catalog to check their overall behavior. We constructed a new method to automatically recognize flares, extract the flare signal from a light-curve base on the adjacent flux-difference array, and calculate flare energy in terms of the synthetic luminosity of binaries. Utilizing this method, we analyzed 3420 Transiting Exoplanet Survey Satellite (TESS) eclipsing binaries, 1330 of which return 9090 flare signals. Based on the result, we provide statistics that show relations between flare behavior and individual component parameters that are obtained from Gaia DR3. The main conclusions include: (1) the flare rate among different spectral types of stars increases from A to M types, and over 60% of M-type stars in binaries have flares; (2) the frequency of flares dN/dE ∼ 1.68 ± 0.05, and this is similar to the most active G-type dwarfs; (3) flares on binaries emit more energy and last longer than those on single stars; (4) the peak ratio of flares is constrained partly by tidal potential, which may lead to multiple nanoflares causing an extended cooling timescale.