Scientists just discovered cannibal stars. Our Sun also once ate Earth-like planets - WION Special

Red dwarf stars are capable of swallowing entire planets, as shown by a new study. Scientists from Keele University and the University of Exeter recently revealed that they spotted signs that at least six such stars ate up nearby planets. Red dwarfs are the most common, smallest, and longest-lived stars in the universe. They published their findings in Monthly Notices of the Astronomical Society, stating that these stars were 50 to 200 million years old and ate Earth-like rocky planets. Even though our Sun has never been a red dwarf and will never be in the future either, it also ate planets when it was still young. Lead author of the study, Professor Robin Jeffries, from Keele University, says it is highly likely that our Sun also did this 4.5 billion years ago. "It is possible and even probable, according to some theoretical models, that our own Sun may have engulfed planetary material (or even planets) early in its life," he told WION.

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The chemical “fingerprint” that revealed the cannibal red dwarf stars

The study focussed on a group of sibling stars all born from the same gas cloud. The main element that gave away six of them as "cannibals" was the presence of lithium. During the initial stages of formation, the intense nuclear reactions would instantly kill all the lithium, leaving them devoid of any. When the researchers scanned through the data of thousands of these stars gathered by the Gaia-ESO Spectroscopic (GES) survey, they noticed that six of them had high lithium content. This fresh lithium could have only come from another body, hinting that these six red dwarf stars pulled in large amounts of material from 3 to 10 Earth-like planets.

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Even though the researchers only found six red dwarf stars that exhibited lithium in their atmosphere, chances are that many more of them could have engulfed planetary material. "Our findings put a lower limit of 2-3% on the frequency of this phenomenon in low-mass red dwarfs. But, it could be higher than this if the engulfed lithium is subsequently destroyed in nuclear fusion reactions," he said.

Why this study matters?

Jeffries says this finding has at least two major implications. First, it can help us understand the formation of our own solar system. "Understanding these early stages of planetary system formation is important in understanding the formation of our own Solar System and whether it is common or unusual," he told WION. Second, it is also vital to know whether munching on planetary material can affect the star itself. “It is important more broadly to understand whether the observed chemical composition of the stars can be affected by planetary engulfment.”

Could this happen to Earth in the future?

The Sun is expected to swallow Earth in approximately 5 billion years. But despite red dwarf stars being most prevalent in the universe, with our own galaxy hosting 75 billion to 160 billion, Earth is never going to fall prey to any of them, says Jeffries.