The Sun may have swallowed a super-Earth, and its fingerprints could still be inside
'Fingerprints' inside the Sun could reveal if it once swallowed a planet
New research in Monthly Notices of the Royal Astronomical Society suggests the young Sun engulfed a super-Earth 5–10 times Earth's mass, leaving a chemical imprint that could explain long-standing solar-model discrepancies—including its depleted lithium and sound-speed structure. Using the MESA stellar-evolution code, the team found the planet could survive its passage through the Sun's outer layers. If these fingerprints are independently detected, it would be strong evidence for an ancient engulfment.
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.
- spectraldrift
This might just be me, but I find metaphors like ''Fingerprints' inside the Sun' harder to read than the title of the original paper, which is probably what should be linked here per HN submission guidelines:
> Planetary engulfment as a solution to solar-model discrepancies and its implications for planetary systems https://doi.org/10.1093/mnras/stag1527
For the press release, something like The Real Sun and Its Simulations Disagree. A Planet That Fell In Early Might Explain It. might be easier to follow.
- mturk
MESA, a piece of software referenced in this article, is a pretty incredible system. (Even referring to it as software underplays the extent of its community and impact.)
Many people are involved in MESA and Bill Paxton was always quick to point out the many new folks that worked on it, but this article does a great job of celebrating his impact:
https://www.kitp.ucsb.edu/news/an-accidental-astrophysicist
It's amazing to me that he went from being the voice on the other end of the Mother Of All Demos to having such a major impact on stellar astrophysics during his "retirement." He passed away in 2025.
- A_D_E_P_T
> Their results favour a scenario in which the young Sun engulfed a super-Earth around 5–10 times the mass of Earth
Given the state of the early solar system, it would be surprising if the Sun didn't swallow a lot of metallic and carbonaceous rocks and pebbles. But it seems unclear to me how the researchers would distinguish between one super-Earth and >10^10 smaller rocks? Chemically I feel the two would be largely the same.
- regularfry
Has someone got a quick explainer for why adding a planet would result in less lithium? Is it just that a super-earth would be big enough and have so little lithium that it would measurably water down the other elements?
- kleton
Nominative determinism- first author's name "Mutlu Yıldız" means "happy star"