Big Island telescope
sees star with dustIt is the closest star to Earth
to be seen with a planet-forming disk
A team headed by University of Hawaii astronomer Michael Liu has discovered the closest star to Earth that has a visible disk of planet-forming dust around it, the UH Institute for Astronomy announced yesterday.
At 33 light-years away, the star AU Microscopium is nearly in our solar system's back yard. And it's young -- 12 million years old -- compared with the sun's estimated age of 4.6 billion years.
"Everything is still fresh and happening around this star," said Liu. In particular, planets are happening.
Using the university's 2.2-meter telescope on Mauna Kea, Liu and colleagues were able to see the disk of gas around the star.
Turning to the British-Dutch-Canadian James Clerk Maxwell submillimeter radio telescope on the mountain, they were able to calculate that the ring of dust was present at a great distance from "AU Mic" but not near it. That strongly suggested that the inner dust has clumped to form planets.
Calculations from observation of other stars nearer to Earth have suggested the presence of planets, but no one has seen them, Liu said. No planets have been seen around AU Mic, either, but this is the first time a star with a dust ring has been seen so close to Earth, he said.
The closest previous discovery of a star with a visible dust ring was 20 years ago when the star beta Pictoris was studied 65 light-years from Earth, he said.
Astronomers are hopeful that the Hubble Space Telescope or one of the giant telescopes on Mauna Kea, which are much bigger than the university telescope, might eventually see the planets.
The discovery by Liu and three colleagues was announced yesterday in the Web site Science Express (www.scienceexpress.org), to be followed by articles in Science magazine and the Astrophysical Journal.
