Searching for GEMS: Three Warm Saturns and a Super-Jupiter Orbiting Four Early M Dwarfs*

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Abstract We report the confirmation and characterization of four transiting giant planets orbiting early M dwarfs discovered by the Searching for GEMS survey: TOI-7189 b, TOI-7265B b, TOI-7393 b, and TOI-7394B b. Joint modeling of Transiting Exoplanet Survey Satellite and ground-based photometry with precision radial velocities from the Habitable-zone Planet Finder and NEID spectrographs yields self-consistent orbital and physical parameters for all systems. The planets have short orbital periods ( P = 1.25–4.17 days), masses spanning from 0.5 M J to 2.1 M J , and radii comparable to Jupiter (0.95 R J < R p < 1.02 R J ). TOI-7189 b (0.50 M J ), TOI-7265B b (0.71 M J ), and TOI-7393 b (0.61 M J ) are Saturn-like in mass and density, whereas TOI-7394B b is a dense super-Jupiter (2.10 M J , ρ p ≈ 2.4 g cm −3 ) on a 1.25-day orbit. All hosts are early M dwarfs with a narrow range of stellar properties, enabling a controlled comparison of giant-planet outcomes around low-mass stars. Three systems orbit super-solar-metallicity stars, while TOI-7393 ([Fe/H] = −0.35 ± 0.16) is the most metal-poor GEMS host identified to date and exhibits kinematics approaching the thin/thick-disk transition, suggestive of an older stellar population. Together, these systems reveal substantial diversity in the masses and bulk properties of short-period giant planets orbiting early M dwarfs, demonstrating that markedly different planetary outcomes can arise around stars with otherwise similar fundamental properties.

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