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Nearby red dwarfs could reveal planet secrets

Wednesday, September 17, 2015

Astronomers found large disks of dust around two of the stars, telltale signs of planets in the process of forming.

Artist's impression of a dusty disk around a red dwarf star.

An accidental find of a collection of young red dwarf stars close to our solar system could give us a rare glimpse of slow-motion planet formation.

Astronomers from the Australian National University (ANU) and University of New South Wales (UNSW) in Canberra found large disks of dust around two of the stars, telltale signs of planets in the process of forming.

“We think the Earth and all the other planets formed from disks like these, so it is fascinating to see a potential new solar system evolving,” said Simon Murphy from the ANU Research School of Astronomy and Astrophysics.

“However, other stars of this age usually don’t have disks any more. The red dwarf disks seem to live longer than those of hotter stars like the Sun. We don’t understand why,” said Murphy. The discovery of objects like these two challenges current theories about planet formation, said Warrick Lawson from UNSW Canberra. “It suggests the planet forming process can endure a lot longer than previously thought,” he said.

The red dwarfs may also host planets that have already formed from the dusty disks, Murphy said. “I think a lot of telescopes will be turned toward them in the next few years to look for planets,” he said.

The giveaway that the red dwarfs had disks around them was an unusual glow in the infrared spectrum of the stars.

Although the disks were not observed directly, Murphy said such close red dwarfs offered a good chance of catching a rare direct glimpse of a disk, or even a planet, by employing specialized telescopes. “Because they are fainter than other stars and there is not as much glare, young red dwarfs are ideal places to directly pick out recently formed planets,” he said.

Lawson said the ability to detect these dim stars has improved dramatically in recent decades, revealing a wealth of information. “Less than 20 years ago, the notion that the nearest part of the galaxy would be littered with young stars was a completely novel one,” he said.

“Most of these objects lie in the southern sky and thus are best accessed by telescopes in the Southern Hemisphere, including those operated by ANU and Australia more broadly.”

Source: www.astronomy.com