Activity of TRAPPIST-1 analogue stars observed with TESS

We present an analysis of TRAPPIST-1 like ultracool dwarfs with TESS full-frame image photometry from the first two years of the primary mission. We constructed a volume-limited sample up to 50 pc, consisting of stars in the vicinity of TRAPPIST-1 on the Gaia color-magnitude diagram. We searched for flares and rotational modulation on the light curves of 248 stars. We determined rotational periods for 42 stars, and estimated the ages of 88 stars using kinematic information. A weak correlation between rotational period and age is observed. The composite flare frequency distribution shows a power-law index similar to TRAPPIST-1, and it is extended to higher energies. The results imply that while superflares can be expected every few decades, the flare rate of such stars is insufficient to fully destroy the possible ozone layer of orbiting planets.