51 Pegasi b orbits a Sun-like G-type star 50 light-years from Earth, a scorching gas giant with a radius of 14.1 × Earth. Completing an orbit every 4.23 days at 0.052 AU, it endures intense radiation far inside the habitable zone. That tight path around a familiar star overturned the idea that giant planets belong only in cold, distant orbits. As the first planet confirmed around a Sun-like star, it opened the era of hot Jupiters and recast planetary systems as restless, migratory places. It stands eternally in the Galactic Codex as the origin chapter of the exoplanet ledger.
