HAT-P-37 is a Sun-like G-type star (about 0.93 solar masses, 5,500 K, 0.88 solar radii), 391 light-years from Earth. HAT-P-37 b is a 1.17-Jupiter-mass companion, with an orbital period of 2.8 days, at 0.038 AU from its star, and an equilibrium temperature near 1,271 K, on an eccentric orbit (e ≈ 0.06), 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.