NASA telescopes finds dust rings around planet-bearing stars

PASADENA, Calif. (AP) – For the first time, scientists have found rings of dust around planet-bearing stars – an important confirmation of theories about how planets form, NASA announced Thursday.

The Spitzer Space Telescope found the rings around five stars about the size and age of the Earth’s sun, which is about 5 billion years old. A ring or disc also was found around a sixth star only a few hundred million years old. All are orbited by gaseous planets.

One scientist compared Spitzer’s discovery to finding bricks left over from construction of a house, since planets are believed to form out of dust clouds.

“It’s a completion of our picture of the planet-formation process,” Alycia Weinberger, an astronomer at the Carnegie Institution of Washington, said during a conference call.

“We really didn’t know of any system that harbored both planets and discs other than our own solar system,” Weinberger said.

No dust discs were seen around 20 other stars known to have planets, although scientists said it is unclear whether that is because they don’t exist or because they glow too faintly with reflected light for Spitzer’s infrared eye to detect.

Charles Beichman, a Spitzer scientist at NASA’s Jet Propulsion Laboratory in Pasadena, said the discovery may help researchers know where to look as they continue to hunt for planets outside our solar system.

Our system has the Kuiper (KYE’-per) Belt, a disc of icy debris beyond the orbit of Neptune. Many comets come from there. The disc is relatively faint, however, and was discovered only about a decade ago.

Also Thursday, NASA announced the Hubble Space Telescope found dust rings around two stars that are much younger and smaller than the sun, at 12 million years for one and 50 to 250 million years for the other. The rings had big gaps in their centers where planets may have swept up the debris, although actual planets have not been confirmed.

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On the Web:

Spitzer Telescope: http://www.spitzer.caltech.edu

AP-ES-12-09-04 2015EST

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