Presentation #320.06 in the session Exoplanets Transits I.
We report the discovery and validation of two long-period gas giants orbiting the early K dwarf TOI 4600 (V=12.6, T=11.9), first detected by the Transiting Exoplanet Survey Satellite (TESS). The inner planet, TOI 4600 b, is 6.88±0.59 Re and has an orbital period of 82.69 d. The outer planet, TOI 4600 c, is 9.42±0.71 Re and has a period range of 226-378 d, having transited only once during TESS observations. We combine TESS photometry and additional ground based spectroscopy, photometry, and high-resolution imaging to validate the two planets. With equilibrium temperatures of 343 K and <270 K, respectively, TOI 4600 b and c add to the small but growing population of temperate gas giants that bridge the gap between hot/warm Jupiters and the solar system gas giants. TOI 4600 is a promising target for further transit and precise RV observations to measure masses and orbits for the planets as well as search for additional non-transiting planets. Together, this system will lend insight into the formation and evolution of planet systems with multiple gas giants.