WASP-3 is a Sun-like F-type star (about 1.62 solar masses, 6,400 K, 1.44 solar radii), 231 light-years from Earth. WASP-3 b is a 2.43-Jupiter-mass companion, with an orbital period of 1.8 days, 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. The planet's large radius (15.9 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.