A Jupiter-size planet that escaped its star’s death

The James Webb Space Telescope has captured a Jupiter‑size exoplanet designated WD 1856 b orbiting a white dwarf star. The planet’s mass and radius place it at roughly the size of Jupiter, yet its host star is a compact white dwarf, the remnant of a star that has already passed through a red‑giant phase. According to the coverage, the planet remains in a close orbit despite the expectation that a star’s expansion during the red‑giant stage would have engulfed or destroyed nearby bodies. Tech Explorist framed the discovery as a planet that “shouldn’t exist,” emphasizing the surprise of its survival after stellar death.

Autoevolution highlighted the striking size ratio, noting the planet is about seven times larger than its white dwarf host. Ars Technica described the object as a Jupiter‑size planet that escaped its star’s death, underscoring the rarity of such a configuration. In standard models, a star’s red‑giant phase expands its outer layers dramatically, often consuming inner planets before shedding its envelope and leaving a dense white dwarf core. Prior detections of planets around white dwarfs have typically involved small, rocky bodies or debris disks, making a gas giant of this scale an outlier.

The survival of WD 1856 b therefore challenges assumptions about orbital migration, tidal forces, and the durability of massive planets during late stellar evolution. Future observations with Webb are expected to refine the planet’s atmospheric composition and orbital parameters, as indicated by the reports. Continued monitoring will test whether the planet’s orbit is stable or undergoing gradual decay. Researchers will also compare WD 1856 b to other white‑dwarf planetary systems to assess how common such survivals might be, setting the stage for forthcoming studies later in 2026.