Discovery of star to give insight into planet origins

By Curtis Lum
Advertiser Staff Writer

Astronomers on Mauna Kea have discovered a young, planet-forming star that scientists hope will provide insight into the origins of our solar system.

The star, AU Microscopium, is surrounded by a dust disk that is "indirect evidence" for newly formed planets, said Michael Liu, an astronomer at the University of Hawai'i Institute for Astronomy. Liu, along with the institute's Jonathan Williams, and the University of California at Berkeley's Paul Kalas and Brenda Matthews, made the discovery from the James Clerk Maxwell telescope on Mauna Kea.

Liu said the AU Mic is 33 light years away and is the nearest star with a visible disk, which scientists believe is the material that forms planets. Up until this discovery, the closest visible dust disk was around Pictoris, a star about 65 light years from the Earth. A light year is the distance that light travels in one year at the rate of 186,282 miles per second.

"We know that extra-solar planets are common, but understanding how they form is an outstanding question," Liu said. "Because AU Mic is so near to Earth, it provides us a special opportunity to examine planet formation in great detail."

AU Mic has half the mass of the sun and is about 12 million years old. Liu said our sun is about 4.6 billion years old.

"Unfortunately, we can't go back in time and observe our own solar system. But by studying these very young stars, we can examine how planets are forming around them, and thus indirectly learn about the origin of our own solar system," Liu said.

He said images of disk around nearby stars are very rare. "Astronomers will be studying AU Mic for many years to come," Liu said.

Reach Curtis Lum at 525-8025 or culum@honoluluadvertiser.com.