An international team of researchers from the United States and Chile has identified compelling chemical evidence that a star consumed one of its orbiting planets. The star, TOI-5882, is a subgiant exhibiting unusually high levels of lithium and other heavy elements in its atmosphere – elements that are typically depleted in older stars through internal mixing processes.
The chemical anomalies observed in TOI-5882 align closely with the theoretical signature expected after a planet is accreted by its host star. Planets often contain higher concentrations of lithium and metals than their parent stars, as they form from the same primordial disk material but do not undergo the same thermal processing. The presence of these elements in the star’s outer layers strongly suggests a recent ingestion event, rather than primordial composition.
TOI-5882 hosts a massive companion, the brown dwarf TOI-5882 b, which orbits in close proximity. Scientists propose that gravitational interactions between this brown dwarf and a second, inner planet could have disrupted the inner planet’s orbit, causing it to spiral inward. Over time, tidal forces would have drawn the planet ever closer until it was ultimately engulfed by the star’s expanding atmosphere.
This discovery provides one of the clearest observational links yet between stellar chemical composition and planetary destruction. While theoretical models have long predicted that stars can consume planets during the late stages of planetary system evolution, direct evidence has remained elusive. This study demonstrates that atmospheric chemical analysis can serve as a powerful tool to uncover past planetary mergers, opening a new pathway in exoplanet dynamics research.
- TOI-5882 shows lithium levels inconsistent with stellar evolution models, pointing to recent planetary accretion.
- The brown dwarf TOI-5882 b likely destabilized the orbit of a nearby planet, triggering its infall.
- Chemical anomalies in stellar atmospheres may serve as forensic evidence of consumed planets.