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 (TESS). TOI-4994b transits a G-type star (V = 12.6 mag) with a mass, radius, and effective temperature of M_⋆ =1.005^+0.064_-0.061 M_⊙, R_⋆ = 1.055^+0.040_-0.037 R_⊙, and T_ eff = 5640 ± 110 K. We obtained follow-up ground-based photometry from the Las Cumbres Observatory (LCO) and the Antarctic Search for Transiting ExoPlanets (ASTEP) telescopes, and we confirmed the planetary nature of TOI-4994b with multiple radial velocity observations from the PFS, CHIRON, HARPS, FEROS, 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= 0.280^+0.037_-0.034 M_J, a radius of R_P= 0.762^+0.030_-0.027R_J, and a Saturn-like bulk density of ρ_p = 0.78^+0.16_-0.14 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.