News Desk · Everything Space
Study suggests the Sun may have swallowed a super-Earth during solar system formation
Image: Universe Today
New modeling shows an engulfed rocky planet could explain why the Sun is lithium-poor and why sound speeds deep inside it don't match standard models.
A new study proposes that some puzzling features of our Sun could be explained if it consumed a large rocky planet billions of years ago, during the early days of the solar system.
Scientists have long noticed that the Sun's outer layer contains far less lithium than expected based on the cloud of gas and dust it formed from, roughly a hundred times less. Researchers have also found a mismatch between measured and modeled sound speeds near the base of the Sun's convection zone, the turbulent layer beneath its surface where heat moves via churning plasma.
A researcher at Ege University in Turkey built models testing whether an engulfed planet could account for both mysteries at once. By simulating various planet sizes and compositions being absorbed into the young Sun, he found that one scenario matched observed solar conditions unusually well.
The best-fitting scenario involved a rocky, lithium-depleted super-Earth roughly 5.6 times the mass of our planet. Such a world could plausibly have formed close to the Sun, inside the orbit of Mercury, and spiraled inward due to gravitational interactions, a process known as planetary migration that has been observed in other star systems.
The modeling doesn't confirm a planet actually was swallowed, but the researcher notes it's notable that a single scenario can resolve multiple solar puzzles simultaneously, including matching other known traits like the depth of the convection zone and the Sun's chemical makeup.
The next step, according to the study's author, is searching for independent observational signatures within the Sun that might confirm whether this ancient planetary meal really happened.
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