Lupus-TR-3 is an orange K-type dwarf (about 0.87 solar masses, 5,000 K, 0.82 solar radii), 773 light-years from Earth. Lupus-TR-3 b is a 0.81-Jupiter-mass companion, with an orbital period of 3.9 days, at 0.046 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. Lupus-TR-3 b skims its star closer than Mercury orbits the Sun.