HAT-P-6 is a Sun-like F-type star (about 1.79 solar masses, 6,570 K, 1.62 solar radii), 275 light-years from Earth. HAT-P-6 b is a 1.32-Jupiter-mass companion, with an orbital period of 3.9 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 (16.6 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.