TOI-4588 is a bright A-type star (about 2.02 solar masses, 7,746 K, 1.57 solar radii), 225 light-years from Earth. TOI-4588 b is a planet with 2.9 Earth radii, with an orbital period of 13.1 days, discovered in 2026 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. Repeated transit observations constrain the planet's orbital inclination and stellar density, anchoring the system's physical scale. The 2026 announcement placed TOI-4588 among the thousands of confirmed planetary systems mapped since the first exoplanet detections.