Searching for GEMS TOI-5349 b is a Saturn-like Planet Orbiting a Metal-rich Early M Dwarf

We report the confirmation and analysis of TOI-5349 b, a transiting, warm, Saturn-like planet orbiting an early M dwarf with a period of ∼3.3 days, which we confirmed as part of the Searching for GEMS survey. TOI-5349 b was initially identified in photometry from NASA’s Transiting Exoplanet Survey Satellite mission and subsequently confirmed using high-precision radial velocity (RV) measurements from the Habitable-zone Planet Finder and MAROON-X spectrographs, and from ground-based transit observations obtained using the 0.6 m telescope at Red Buttes Observatory and the 1.0 m telescope at the Table Mountain Facility of Pomona College. From a joint fit of the RV and photometric data, we determine the planet’s mass and radius to be 0.40 ± 0.02 M_J (127.4+5.9-5.7 M_⊕) and 0.91 ± 0.02 R_J (10.2 ± 0.3 R_⊕), respectively, resulting in a bulk density of ρp = 0.66 ± 0.06 g cm⁻³ (∼0.96 the density of Saturn). We determine that the host star is a metal-rich M1-type dwarf with a mass and radius of 0.61 ± 0.02 M_⊙ and 0.58 ± 0.01 R_⊙, and an effective temperature of T_eff = 3751 ± 59 K. Our analysis highlights an emerging pattern, exemplified by TOI-5349, in which transiting Giant Exoplanets around M dwarf Stars (GEMS) often have Saturn-like masses and densities and orbit metal-rich stars. With the growing sample of GEMS planets, comparative studies of short-period gas giants orbiting M dwarfs and Sun-like stars are needed to investigate how metallicity and disk conditions shape the formation and properties of these planets.