Confirmation of a Sub-Saturn-size Transiting Exoplanet Orbiting a G Dwarf: TOI-1194 b and a Very Low Mass Companion Star: TOI-1251 B from TESS

Abstract

We report the confirmation of a sub-Saturn-size exoplanet, TOI-1194 b, with a mass of about 0.456-+0.0510.055 MJ, and a very low mass companion star with a mass of about 96.5 ± 1.5 MJ, TOI-1251 B. Exoplanet candidates provided by the Transiting Exoplanet Survey Satellite (TESS) are suitable for further follow-up observations by ground-based telescopes with small and medium apertures. The analysis is performed based on data from several telescopes worldwide, including telescopes in the Sino-German multiband photometric campaign, which aimed at confirming TESS Objects of Interest (TOIs) using ground-based small-aperture and medium-aperture telescopes, especially for long-period targets. TOI-1194 b is confirmed based on the consistent periodic transit depths from the multiband photometric data. We measure an orbital period of 2.310644 ± 0.000001 days, the radius is 0.767-+0.0410.045 RJ and the amplitude of the RV curve is 69.4-+7.37.9 m s−1. TOI-1251 B is confirmed based on the multiband photometric and high-resolution spectroscopic data, whose orbital period is 5.963054-+0.0000010.000002 days, radius is 0.947-+0.0330.035 RJ and amplitude of the RV curve is 9849-+4042 m s−1