Three warm Jupiters orbiting TOI-6628, TOI-3837, and TOI-5027 and one sub-Saturn orbiting TOI-2328

We report the discovery and characterization of three new transiting giant planets orbiting TOI-6628, TOI-3837, and TOI-5027 and one new warm sub-Saturn orbiting TOI-2328, whose transits events were detected in the light curves of the Transiting Exoplanet Survey Satellite (TESS) space mission. By combining TESS light curves with ground-based photometric and spectroscopic followup observations, we confirm the planetary nature of the observed transits and radial velocity variations. TOI-6628 b has a mass of 0.74±0.06 M_J and a radius of 0.98⁺₋⁰₀⁰⁶₀₅ R_J and orbits a metal-rich star with a period of 18.18424±0.00001 days and an eccentricity of 0.670⁺₋⁰₀⁰¹⁵₀₁₆, making it one of the most eccentric orbits of all known warm giants. TOI-3837 b has a mass of 0.59±0.05 M_J and a radius of 0.97⁺₋⁰₀⁰⁵₀₆ R_J and orbits its host star every 11.88865±0.00003 days, with a moderate eccentricity of 0.221₋⁺₀⁰₀₄₆⁰⁴². With a mass of 2.02±0.13 M_J and a radius of 0.96⁺₋⁰₀⁰⁵₀₆ R_J, TOI-5027 b orbits its host star in an eccentric orbit with e = 0.385⁺₋⁰₀⁰²⁵₀₂₆ every 10.24368±0.00001 days. TOI-2328 b is a Saturn-like planet with a mass of 0.16±0.02 M_J and a radius of 0.89₋⁺₀⁰₀₅⁰⁴ R_J; it orbits its host star in a nearly circular orbit with e = 0.057⁺₋⁰₀⁰⁴⁶₀₂₉ at a period of 17.10197±0.00001 days. All four planets have orbital periods above ten days, and our planet’s interior structure models are consistent with a rocky-icy core with an H/He envelope, providing evidence supporting the core-accretion model of planet formation for this kind of planet.