Induced-Flare Candidates from the TESS Mission

Abstract

The empirical underabundance of close-in planets with radii 1.5-2.0 times that of the Earth, referred to as the radius irradiation valley, may be linked to the inability of gas dwarfs under certain conditions to retain their volatile envelopes due to photoevaporation or core-powered mass loss. In either case, the extent to which a planet can preserve its atmosphere critically depends on poorly understood planetary magnetism. An effective probe of planetary magnetic fields is the interaction between a star and its close-in planet, where the planet magnetically interacts with its host, inducing flares as it moves near its periastron within the Alfv\'en surface of its host star. We construct a pipeline, \textsc{ardor}, to detect and characterize potentially planet-induced flares in time-series photometric data using a physically motivated forward model of star-planet interactions, with a focus on recovering flares located near the noise floor. We perform extensive injection-recovery simulations to determine our sensitivity to flares correlating with the planetary phase over a range of stellar types and orbital architectures. We identify one close-in, eccentric ($e=0.18$) system, TOI-1062\,b, which exhibits flaring during periastron consistent with being induced with $p_{KS}=2.2\times10^{-5}$ and a $5.1\sigma$ detection through unbinned likelihood analysis and goodness-of-fit tests. We also identify an additional eccentric ($e=0.363$) candidate, Gliese 49b, which exhibits moderately significant ($2.5\sigma$) flare clustering at periastron, requiring additional photometric observations to confirm its significance. TOI-1062b and Gliese 49b are promising candidates for induced flares, underscoring the need for radio and UV follow-up observations.