CoRoT-18 is a Sun-like G-type star (about 0.95 solar masses, 5,440 K, 1.00 solar radii), 765 light-years from Earth. CoRoT-18 b is a 3.47-Jupiter-mass companion, with an orbital period of 1.9 days, at 0.029 AU from its star, and an equilibrium temperature near 1,550 K, on an eccentric orbit (e ≈ 0.08), discovered in 2011 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.