A study published in Monthly Notices of the Royal Astronomical Society suggests the young Sun may have swallowed a planet 5 to 10 times Earth’s mass billions of years ago, leaving a chemical trace deep inside the star. The model, built by Mutlu Yildiz, points to a Super-Earth-mass body as the best fit for the Sun’s interior and its lithium shortfall.
That is why the finding is drawing attention now: it offers a fresh answer to a long-running solar puzzle. Yildiz said the work began with two problems that standard solar models struggled to match — the structure of the Sun’s convection zone and the surface’s unusually low lithium compared with similarly sized stars. By testing accretion scenarios with an open-source module for stellar evolution, he found that the best-fitting case included the Sun consuming a super-Earth-mass planet billions of years ago.
The number matters because it is not a vague match. Yildiz said the calculations converged on a specific mass range and that the results line up with known measurements of the Sun’s interior and lithium content. In his telling, the engulfed world would have been made of material chemically different from the gas in the disc around the young Sun, so if it fell in early enough it could have changed the star’s makeup in a way that still shows up today. He said the work suggests the Sun itself may still carry evidence of that event.
Even so, the paper stops short of saying the case is closed. It says planetary engulfment might affect solar structure and that the calculations make the idea physically plausible, but it does not confirm that the Sun actually swallowed a Super-Earth. That gap matters, because a model that fits the numbers is not the same as a direct detection of the footprint the model predicts.
Yildiz said the next step is to see whether those fingerprints can be independently detected. If they can, the Sun would not just be a star with a lithium problem and an awkward convection zone. It would be a star with a buried record of a lost planet, one that may have vanished billions of years ago but still left its mark where no telescope can see it directly.
