HD 212301 is a Sun-like F-type star (about 1.55 solar masses, 6,239 K, 1.16 solar radii), 54.2 light-years from Earth. HD 212301 b is a 0.51-Jupiter-mass companion, with an orbital period of 2.2 days, at 0.030 AU from its star, discovered in 2005 via radial velocity. The inner world is a hot Jupiter — a gas giant hugging its star at a fraction of Mercury's distance — a class that forced astronomers to rethink how giant planets form and migrate inward. HD 212301 b skims its star closer than Mercury orbits the Sun.