HAT-P-22 is a Sun-like G-type star (about 1.13 solar masses, 5,302 K, 1.11 solar radii), 81.8 light-years from Earth. HAT-P-22 b is a 2.47-Jupiter-mass companion, with an orbital period of 3.2 days, discovered in 2010 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 (12.9 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.