HATS-13 is a Sun-like G-type star (about 0.96 solar masses, 5,523 K, 0.89 solar radii), 422 light-years from Earth. HATS-13 b is a 0.54-Jupiter-mass companion, with an orbital period of 3.0 days, at 0.041 AU from its star, and an equilibrium temperature near 1,244 K, on an eccentric orbit (e ≈ 0.18), discovered in 2015 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.