2022AJ....164...71V

As an all-sky survey, NASA's Transiting Exoplanet Survey Satellite (TESS) mission is able to detect the brightest and rarest types of transiting planetary systems, including young planets that enable study of the evolutionary processes that occur within the first billion years. Here we report the discovery of a young, multiplanet system orbiting the bright K4.5V star, TOI-712 (V = 10.838, M_* = 0.733_–0.025^+0.026 M_☉, R_* = 0.674 ± 0.016 R_☉, T_eff=4622_–60⁺⁶¹ K). From the TESS light curve, we measure a rotation period of 12.48 days and derive an age between about 500 Myr and 1.1 Gyr. The photometric observations reveal three transiting mini-Neptunes R_b=2.049_–0.080^+0.120 R_⊕, R_c = 2.701_–0.082^+0.092 R_⊕, R_d= 2.474_–0.082^+0.090R_⊕), with orbital periods of P_b = 9.531 days, P_c = 51.699 days, and P_d = 84.839 days. After modeling the three-planet system, an additional Earth-sized candidate is identified, TOI-712.05 (P = 4.32 days, R_P = 0.81 ± 0.11 R_⊕). We calculate that the habitable zone falls between 0.339 and 0.844 au (82.7 and 325.3 days), placing TOI-712 d near its inner edge. Among planetary systems harboring temperate planets, TOI-712 (T = 9.9) stands out as a relatively young star bright enough to motivate further characterization.