TOI-3819 is a Sun-like G-type star (about 1.24 solar masses, 5,859 K, 1.54 solar radii), 558 light-years from Earth. TOI-3819 b is a 1.11-Jupiter-mass companion, with an orbital period of 3.2 days, at 0.046 AU from its star, and an equilibrium temperature near 1,633 K, discovered in 2023 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.