WASP-1 is a Sun-like F-type star (about 1.24 solar masses, 6,110 K, 1.47 solar radii), 393 light-years from Earth. WASP-1 b is a 0.85-Jupiter-mass companion, with an orbital period of 2.5 days, at 0.039 AU from its star, discovered in 2007 via transit. 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. WASP-1 b skims its star closer than Mercury orbits the Sun.