Search to look for 'siblings' of our sun

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SYDNEY, April 11 (UPI) -- Australian astronomers say they will hunt for long-lost "siblings" of our sun, formed from the same cloud of dust and gas that gave birth to our star.

The interstellar cloud that spawned the sun 4.6 billion years ago has long since vanished, but most of the stars born with it must still shine somewhere in the Milky Way, they said.

Stars form either in loose groups of a few dozen similar in mass to the sun and smaller, or in large clusters containing hundreds or thousands of stars spanning a wide range of masses.

Primordial meteorites in our solar system contain compounds that can only have formed from the decay of radioactive isotopes produced when a massive star explodes in a supernova, researchers said, and the abundance of such compounds tells us that the sun grew up less than 1 light year away from a massive star that exploded, suggesting the sun's "nursery" was a large star cluster.

Previous studies have concluded the sun's star cluster probably had at least 1,000 members, and Joss Bland-Hawthorn at the University of Sydney, says he wants to look for them.

"I'm utterly fascinated by anything historical," he said. "I would love to know whether we can identify stars that were born with our sun."

Bland-Hawthorn and his colleagues will use a new instrument called HERMES attached to a telescope in New South Wales to look at the chemical make-up of more than a million stars up to 20,000 light years away, hoping to find stars with a chemical make-up matching the sun's, NewScientist.com reported.

"I wish I could tell you that it's going to be easy," Bland-Hawthorn said. "It's going to be a 10-year mission to try to crack this."