WASP-66 is a Sun-like F-type star (about 1.33 solar masses, 6,600 K, 1.76 solar radii), 500 light-years from Earth. WASP-66 b is a 2.35-Jupiter-mass companion, with an orbital period of 4.1 days, discovered in 2012 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 (15.7 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.