Discovery and Characterization of an Eccentric, Warm Saturn Transiting the Solar Analog TOI-4994

We present the detection and characterization of TOI-4994b (TIC 277128619b), a warm Saturn-sized planet discovered by the NASA Transiting Exoplanet Survey Satellite. TOI-4994b transits a G-type star ( V = 12.6 mag) with a mass, radius, and effective temperature of M ⋆ = 1.00 5 − 0.061 + 0.064 M ⊙ , R ⋆ = 1.05 5 − 0.037 + 0.040 R ⊙ , and T eff = 5640 ± 110 K. We obtained follow-up ground-based photometry from the Las Cumbres Observatory and the Antarctic Search for Transiting ExoPlanets telescopes, and we confirmed the planetary nature of TOI-4994b with multiple radial velocity observations from the Planet Finder Spectrograph, CHIRON, High Accuracy Radial velocity Planet Searcher, Fiber-fed Extended Range Optical Spectrograph, and CORALIE instruments. From a global fit to the photometry and radial velocities, we determine that TOI-4994b is in a 21.5 day eccentric orbit ( e = 0.32 ± 0.04) and has a mass of M P = 0.28 0 − 0.034 + 0.037 M J , a radius of R P = 0.76 2 − 0.027 + 0.030 R J , and a Saturn-like bulk density of ρ p = 0.7 8 − 0.14 + 0.16 g cm - 3 . We find that TOI-4994 is a potentially viable candidate for follow-up stellar obliquity measurements. TOI-4994b joins the small sample of warm Saturn analogs and thus sheds light on our understanding of these rare and unique worlds.