A Jupiter-sized planet named WD 1856 b orbits a white dwarf, the remnant of a Sun-like star, and is the only confirmed planet to survive its host’s red‑giant phase. Astronomers identified the planet in 2020 when the TESS mission surveyed about 2,000 white dwarfs for transiting objects. The planet was detected as a gas giant that produces a half‑size dip in the star’s brightness during a grazing transit, an unusual geometry. The white dwarf is roughly seven times smaller than the planet, which circles at 0.02 astronomical units, contrary to models that predict outer planets should move outward after a star sheds its envelope. The planet’s temperature measured by the James Webb Space Telescope on April 27, 2023, is about 400 kelvin, far higher than the 150–200 kelvin expected for a Jupiter‑like world at that distance. The excess heat suggests an internally generated source, likely from a prior migration event. Modeling indicates the reheating probably occurred 3–5.5 billion years after the star became a white dwarf, a timeline that matches a high‑eccentricity migration scenario involving gravitational interactions with two distant stellar companions. The common‑envelope scenario is less likely because it would have ended before the observed temperature could develop. The planet’s atmosphere contains roughly 7 percent methane, about twenty times the fraction assumed in standard cooling models, which may have affected previous temperature estimates. Updated atmospheric models are needed to refine the evolutionary history. WD 1856 lies about 75 light‑years from Earth, making it a nearby candidate for further study. Additional JWST observations of the system are planned. The discovery highlights the possibility that other planets may have survived stellar death, but confirmation requires more data.