KELT-8 is a Sun-like G-type star (about 0.81 solar masses, 5,754 K, 1.46 solar radii), 198 light-years from Earth. KELT-8 b is a 0.66-Jupiter-mass companion, with an orbital period of 3.2 days, discovered in 2015 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 (18.2 Earth radii) indicates a bloated atmosphere heated by intense stellar radiation.