TOI-5344 b: A Saturn-like Planet Orbiting a Super-solar Metallicity M0 Dwarf

We confirm the planetary nature of TOI-5344 b as a transiting giant exoplanet around an M0-dwarf star. TOI-5344 b was discovered with the Transiting Exoplanet Survey Satellite photometry and confirmed with ground-based photometry (the Red Buttes Observatory 0.6 m telescope), radial velocity (the Habitable-zone Planet Finder), and speckle imaging (the NN-Explore Exoplanet Stellar Speckle Imager). TOI-5344 b is a Saturn-like giant planet (ρ = 0.80 ${}_{-0.15}^{+0.17}$ g cm^-3) with a planetary radius of 9.7 ± 0.5 R _⊕ (0.87 ± 0.04 R _Jup) and a planetary mass of ${135}_{-18}^{+17}\ {M}_{\oplus }$ (0.42 ${}_{-0.06}^{+0.05}\ {M}_{\mathrm{Jup}}$ ). It has an orbital period of ${3.792622}_{-0.000010}^{+0.000010}$ days and an orbital eccentricity of ${0.06}_{-0.04}^{+0.07}$ . We measure a high metallicity for TOI-5344 of [Fe/H] = 0.48 ± 0.12, where the high metallicity is consistent with expectations from formation through core accretion. We compare the metallicity of the M-dwarf hosts of giant exoplanets to that of M-dwarf hosts of nongiants (≲8 R _⊕). While the two populations appear to show different metallicity distributions, quantitative tests are prohibited by various sample caveats.