Ross 128 is a cool M-dwarf (about 0.17 solar masses, 3,192 K, 0.20 solar radii), 11 light-years from Earth. Ross 128 b is a temperate, roughly Earth-mass planet about 11 light-years away, around a relatively quiet red dwarf. Ross 128 b is a 1.4-Earth-mass planet, with an orbital period of 9.9 days, at 0.050 AU from its star, and an equilibrium temperature near 301 K, on an eccentric orbit (e ≈ 0.12), discovered in 2017 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.