A giant planet has been found orbiting perilously close to its host star — a white dwarf — after surviving the star's violent transformation into a red giant. This makes it one of the few known planets to endure such a stellar cataclysm, according to astronomers who announced the discovery.
The planet was detected through its gravitational influence on the white dwarf, causing subtle shifts in the star's light. Its close orbit places it within what was once the red giant's envelope, a region where planets are typically expected to be engulfed and destroyed. The discovery raises questions about how the planet survived and ended up in its current position.
Researchers plan to use the James Webb Space Telescope (JWST) to study the planet's atmosphere and composition. JWST's infrared sensitivity could reveal whether the planet formed in a more distant orbit and migrated inward, or if it originated close to the star and somehow survived the red giant phase.
The finding has implications for understanding planetary system evolution and the fate of our own Solar System. When the Sun expands into a red giant in about 5 billion years, it will likely engulf Mercury, Venus, and possibly Earth. This discovery suggests that some planets can survive such an event under certain conditions.
A counterargument to the survival hypothesis is that the planet may have been captured after the star's death, rather than being a survivor from the main sequence era. Further JWST observations are needed to distinguish between these scenarios and confirm the planet's origin story.