<i>Searching for GEMS</i> : TOI-5349 b is a Saturn-like Planet Orbiting a Metal-rich Early M Dwarf

Abstract 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 ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>127</mml:mn> <mml:mo>.</mml:mo> <mml:msubsup> <mml:mrow> <mml:mn>4</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>5.7</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>+</mml:mo> <mml:mn>5.9</mml:mn> </mml:mrow> </mml:msubsup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊕</mml:mo> </mml:mrow> </mml:msub> </mml:math> ) and 0.91 ± 0.02 R J (10.2 ± 0.3 R ⊕ ), respectively, resulting in a bulk density of ρ p = 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.