Solar interior signatures may indicate past planetary engulfment

Researchers have identified subtle chemical signatures in the Sun’s outer layers that could indicate the star once engulfed a planetary body. The findings, presented by a team from the Royal Astronomical Society, rely on high‑precision spectroscopic measurements that reveal anomalous abundances of refractory elements—those that condense at high temperatures—within the solar photosphere. Such “fingerprints” are consistent with the accretion of material similar in composition to Earth‑like planets, suggesting a past event in which the Sun consumed a planet or planetary debris during its early evolution.

The analysis compared the Sun’s elemental ratios to those of solar twins—stars with comparable mass and age—to isolate deviations that cannot be explained by standard stellar nucleosynthesis. Elevated levels of iron, nickel, and other heavy elements, alongside a depletion of volatile substances, align with theoretical models of planetary ingestion. The researchers caution that while the data support the ingestion hypothesis, alternative processes such as internal mixing could also produce comparable signatures. Nonetheless, the study provides a novel method for probing the histories of stars and may help astronomers assess the frequency of planet‑star collisions in other planetary systems.

The discovery adds a new dimension to our understanding of solar system formation, offering a potential record of early dynamical events that shaped the Sun’s composition. Future observations of similar chemical anomalies in other stars could refine estimates of how often stars consume planets, informing models of planetary system stability and evolution.