WASHINGTON (Reuters) - Chemical elements observed around a burned-out star known as a white dwarf offer evidence Earth-like planets once orbited it, suggesting that worlds like our own may not be rare in the cosmos, scientists said on Thursday.
Astronomers at the University of California, Los Angeles and University of Kiel in Germany studied a white dwarf called GD 362 located 150 light-years away in our Milky Way galaxy.
They figured out the chemical composition of a large asteroid that was ripped apart by gravitational forces as it approached GD 362, finding it was similar to the Earth's crust. It was rich in iron and calcium and low in carbon, much like a strong rock, they said.
The white dwarf is surrounded by dusty rings, probably made up of objects shredded as they ventured too close.
"It's probably quite similar to Saturn's rings," UCLA astronomer Michael Jura said in a telephone interview.
GD 362 once was a star similar to the sun. After billions of years, it ballooned into a "red giant" as part of its death process, expelling most of its outer material, then degenerated into a burnt-out remnant called a white dwarf.
The fact that the asteroid is so similar in make-up to the Earth, as well as the moon, indicates that rocky planets like our own may have orbited the star eons ago, Jura said.
And if such planets currently populate our solar system and existed in a planetary system around this white dwarf, they may well be fairly common in the universe, Jura added.
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