GJ 251 is a cool M-dwarf (about 0.35 solar masses, 3,342 K, 0.36 solar radii), 5.6 light-years from Earth. GJ 251 b is a 3.9-Earth-mass planet, with an orbital period of 14.2 days, at 0.081 AU from its star, and an equilibrium temperature near 336 K, discovered in 2020 via radial velocity. GJ 251 c is a 3.9-Earth-mass planet, with an orbital period of 53.6 days, at 0.196 AU from its star, and an equilibrium temperature near 216 K, discovered in 2025 via radial velocity.