GJ 720 A is a cool M-dwarf (about 0.57 solar masses, 3,837 K, 0.56 solar radii), 15.6 light-years from Earth. GJ 720 A b is a 13.6-Earth-mass planet, with an orbital period of 19.5 days, at 0.119 AU from its star, and an equilibrium temperature near 401 K, on an eccentric orbit (e ≈ 0.12), discovered in 2021 via radial velocity. The planet betrayed itself through the star's reflex motion — a technique that first revealed worlds around Sun-like stars in the 1990s and remains a workhorse of exoplanet discovery.