A study published in Monthly Notices of the Royal Astronomical Society proposes that the Sun may have engulfed a super-Earth 5 to 10 times the mass of Earth early in its history, leaving detectable chemical and structural imprints. The research, led by Professor Mutlu Yildiz of Ege University in Turkey, uses stellar-evolution models to explore how such an event could explain long-standing discrepancies in solar observations, including the Sun’s lithium depletion and anomalies in helioseismic data.
Sun May Have Consumed Super-Earth 5–10 Times Earth’s Mass, Study Suggests
Chemical and Structural Clues in the Sun’s Interior
The study suggests that a super-Earth’s engulfment could have altered the Sun’s internal composition, affecting its sound-speed profile and convection-zone depth. Helioseismic measurements—akin to medical imaging of the Sun’s interior—reveal that the speed of sound near the bottom of the convection zone does not align with standard solar models. Yildiz and colleagues found that incorporating a planetary engulfment scenario improved agreement with these observations. 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.
Link to Previous Theoretical Work
The study builds on earlier research, including a 2016 paper by Martin & Livio, which proposed that super-Earths could have formed within Mercury’s orbit and migrated inward, potentially falling into the Sun. While that work outlined a theoretical pathway for such an event, it did not confirm whether a planet was actually swallowed. Yildiz’s team now asks whether the Sun itself could retain evidence of this process. The next step is to see if these fingerprints can be independently detected,
Yildiz said.
The research also highlights the rarity of super-Earths in our solar system compared to other star systems. The solar system may once have contained a world several times larger than Earth that no longer exists,
the study notes. Rather than being ejected into interstellar space or colliding with another planet, it may have disappeared inside the Sun.
Future Observations and Verification
While the study does not prove the Sun consumed a super-Earth, it offers a compelling explanation for multiple solar anomalies. The team used the MESA stellar-evolution code to simulate various planetary engulfment scenarios, finding that a rocky super-Earth of 5.6 Earth masses best matched observed solar characteristics. If the predicted structural and chemical signature could be independently identified through helioseismic or other observations, it would provide strong evidence for such an event happening billions of years ago,
Yildiz stated.
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