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 time-series 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 d, 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.