HATS-40 is a Sun-like F-type star (about 1.56 solar masses, 6,460 K, 2.26 solar radii), 1,342 light-years from Earth. HATS-40 b is a 1.59-Jupiter-mass companion, with an orbital period of 3.3 days, at 0.050 AU from its star, and an equilibrium temperature near 2,101 K, on an eccentric orbit (e ≈ 0.31), discovered in 2018 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.