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

Abstract

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 ⊕ (0.42 − 0.06 + 0.05 M 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.