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

We report the confirmation of a sub-Saturn-size exoplanet, TOI-1194 b with a mass about 0.456_-0.051^+0.055 MJ, and a very low mass companion star with a mass of about 96.47±1.5 M_J, 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 multi-band 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 transits depths from the multiband photometric data. We measure an orbital period of 2.310644±0.000001d, and radius is 0.767_-0.041^+0.045RJ, and amplitude of RV curve is 69.36_-7.31^+7.90 m/s. TOI-1251 B is confirmed based on the multi-band photometric and high-resolution spectroscopic data, whose orbiting period is 5.963054_-0.000001^+0.000002d, the radius is 0.947_-0.033^+0.035RJ, and amplitude of RV curve is 9848.87_-40.08^+41.86m/s