HATS-42 is a Sun-like F-type star (about 1.27 solar masses, 6,060 K, 1.48 solar radii), 800 light-years from Earth. HATS-42 b is a 1.88-Jupiter-mass companion, with an orbital period of 2.3 days, at 0.037 AU from its star, and an equilibrium temperature near 1,856 K, on an eccentric orbit (e ≈ 0.23), 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.