CoRoT-1 is a Sun-like G-type star (about 0.95 solar masses, 5,950 K, 1.11 solar radii), 788 light-years from Earth. CoRoT-1 b was the first exoplanet detected by its changing optical phase curve, brightening and fading as it orbits. CoRoT-1 b is a 1.03-Jupiter-mass companion, with an orbital period of 1.5 days, and an equilibrium temperature near 1,898 K, 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 (16.7 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.