K2-321 is an orange K-type dwarf (about 0.58 solar masses, 3,750 K, 0.59 solar radii), 77.7 light-years from Earth. K2-321 b is a planet with 2.1 Earth radii, with an orbital period of 2.3 days, at 0.028 AU from its star, and an equilibrium temperature near 830 K, on an eccentric orbit (e ≈ 0.44), discovered in 2020 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.