Billions of years ago, the infant sun may have devoured a super-Earth several times larger than our own world. According to new research published in the Monthly Notices of the Royal Astronomical Society, this violent collision left distinct chemical fingerprints deep inside our star.
Decoding the Sun’s Lithium Deficit
For decades, astronomers have struggled to reconcile standard stellar evolution models with persistent quirks in our star’s composition. Several long-standing puzzles include: the depth of the sun’s convection zone, subtle discrepancies in its internal sound-speed structure, and a surface that is heavily depleted of lithium.
To untangle these mysteries, a research team led by Mutlu Yildiz of Ege University in Turkey turned to advanced stellar evolution software. They simulated how the young sun interacted with its protoplanetary disk—the massive, flattened cloud of gas and dust swirling around infant stars where shifting material constantly alters environmental dynamics.
Simulating an Ancient Planetary Collision
By running these detailed computer models, Yildiz and his colleagues tested whether an early planetary impact could permanently alter a star’s internal chemistry. The simulations revealed a striking match: the engulfment of a super-Earth, defined as a planet between five and ten times the mass of Earth, accounted for the sun’s peculiar observed characteristics better than any other scenario.
“Our new study suggests that a planet several times more massive than Earth may have fallen into the young sun and left a lasting chemical imprint deep inside it,” Yildiz said in a statement.
Addressing Missing Super-Earths
Beyond clarifying internal solar anomalies, this cosmic cannibalism hypothesis helps resolve a major architectural mystery regarding our solar system: why our local neighborhood lacks close-in super-Earths, which astronomers routinely observe orbiting other distant stars.
Previous studies indicate that one or more super-Earths may have originally formed near the orbit of Mercury. Over time, these bodies migrated inward, ultimately plunging directly into the infant sun.
Theoretical Models and Future Tests
Despite the precision of the computer simulations, which successfully converged on a specific mass range for the devoured planet, the researchers caution that the work is purely theoretical. The modeling does not definitively prove the collision took place, and alternative explanations for the sun’s structural anomalies still exist.
Even so, the team remains optimistic. They believe targeted future observations could independently detect the chemical and structural fingerprints predicted by their models, hiding quietly inside our sun.
Keep reading