A Search for Non-Transiting Exoplanets with Optical Light Phase Curves from TESS Southern Ecliptic Sectors

Abstract

Abstract Phased photometric variation provides a method for discovering potential non-transiting exoplanets in high-precision timeseries photometry. Applying a Lomb-Scargle algorithm, we search for phased photometric variation in a selection of 140,000 bright dwarf stars with full frame image light-curves from the southern ecliptic hemisphere of the Transiting Exoplanet Survey Satellite (TESS) mission. We fit the phased photometric variation signal for these candidates using a three-component model comprised of atmospheric reflection/emission, tidal ellipsoidal distortion, and Doppler beaming contributions. We find 27 candidate signals that can be attributed to short-period, massive planets. Our candidates have periods ranging from 0.74 to 1.98 days, and photometric variations with amplitudes ranging from 94 to 528 ppm. The host stars are all bright (9<T<11) F and G type dwarf stars. We estimate the radial velocity semi-amplitudes to be in excess of 60 m s−1 for each candidate, easily within reach of current high-precision spectrographs. If confirmed, these candidates would be the first non-transiting exoplanets discovered with TESS.