TrES-3 is a Sun-like G-type star (about 0.93 solar masses, 5,650 K, 0.83 solar radii), 231 light-years from Earth. TrES-3 b is a 1.91-Jupiter-mass companion, with an orbital period of 1.3 days, at 0.023 AU from its star, discovered in 2007 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. TrES-3 b skims its star closer than Mercury orbits the Sun.