CoRoT-3 is a Sun-like F-type star (about 1.37 solar masses, 6,740 K, 1.56 solar radii), 769 light-years from Earth. CoRoT-3 b is a 21.7-Jupiter-mass companion, with an orbital period of 4.3 days, discovered in 2008 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 (11.3 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.