55 Cnc B is a cool M-dwarf (about 0.26 solar masses, 3,286 K, 0.27 solar radii), 12.5 light-years from Earth. 55 Cnc B b is a 3.5-Earth-mass planet, with an orbital period of 6.8 days, at 0.044 AU from its star, discovered in 2025 via radial velocity. 55 Cnc B c is a 5.3-Earth-mass planet, with an orbital period of 33.7 days, at 0.130 AU from its star, discovered in 2025 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.