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Study: Sun-like star ate some of its planets

"It can be very hard to know the history of a particular star, but once in a while we get lucky," said astronomer Debra Fischer.

By
Brooks Hays
An illustration shows a planet being consumed by its sun. Photo by Gabi Perez/Instituto de Astrofísica de Canarias
An illustration shows a planet being consumed by its sun. Photo by Gabi Perez/Instituto de Astrofísica de Canarias

CHICAGO, Dec. 15 (UPI) -- Scientists have discovered evidence that a distant star has consumed a few of its planets. The star, HIP68468, is located 300 light-years away, and is similar in size, mass and luminosity to Earth's sun. For this reason, it is one several stars known as a "solar twin."

Analysis of the solar twin's composition suggests it has "eaten" some of the planetary residents in its system. Researchers detailed the discovery in a new paper published in the journal Astronomy & Astrophysics.

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"It doesn't mean that the sun will 'eat' the Earth any time soon," study co-author Jacob Bean, assistant professor of astronomy and astrophysics at the University of Chicago, said in a news release. "But our discovery provides an indication that violent histories may be common for planetary systems, including our own."

Studying the relationship between solar twins and their planets is an ideal way to understand the evolution of our own solar system, and the latest findings may offer clues as to how our solar system will evolve. Models of our solar system predict Mercury will eventually be swallowed by the sun.

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HIP68468 is six billion years old. It features four times the amount of lithium expected for a star its age, evidence it has ingested a few planets in its recent past. The star also boasts larger-than-expected amounts of heat-resistant metals abundant on rocky planets.

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"It can be very hard to know the history of a particular star, but once in a while we get lucky and find stars with chemical compositions that likely came from in-falling planets," said Debra Fischer, a professor of astronomy at Yale University who was not involved in the latest research. "That's the case with HD68468. The chemical remains of one or more planets are smeared in its atmosphere."

"It's as if we saw a cat sitting next to a bird cage," Fischer added. "If there are yellow feathers sticking out of the cat's mouth, it's a good bet that the cat swallowed a canary."

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