HIP 107772 is a cool M-dwarf (about 0.63 solar masses, 4,006 K), 23.6 light-years from Earth. HIP 107772 b is a 12.9-Earth-mass planet, with an orbital period of 55.2 days, at 0.243 AU from its star, on an eccentric orbit (e ≈ 0.18), discovered in 2020 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. The planet's marked eccentricity suggests past scattering events or perturbations from unseen companions.