HILO, Hawai'i — New evidence collected by astronomers at Mauna Kea observatories suggest the dust disks surrounding stars disappear early in the life of the stars, which implies the stars have less time than theorists suspected to begin forming planets.

The dust disks made up of tiny particles are believed to provide the raw material for planets, and the news observations suggest the disks disappear rapidly, giving the stars only a few million years to get started on making planets.

That may sound like a long time, but astronomers said it isn't compared with the life of a star. If a typical star's 10-billion-year lifetime were compressed to the average human lifespan, the disks would disappear within the first week.

University of Hawai'i graduate student Sean Andrews and Dr. Jonathan Williams of the Institute for Astronomy presented their findings at the national meeting of the American Astronomical Society in Washington, D.C., yesterday.

Using sensitive radio cameras on the 49-foot James Clerk Maxwell Telescope and 32.8-foot Caltech Submillimeter Observatory at Mauna Kea, astronomers studied the swirling disks of gas and dust around young stars in the Taurus region of the sky.

"The dust is either being dispersed, dumped onto the star, or growing into large clumps that are difficult to detect," Andrews said.

Previous work at shorter, infrared wavelengths had shown that the innermost regions of disks disappear rapidly, but it was thought that the outer parts, where the planets in our solar system reside and which are most visible at longer radio wavelengths, would last substantially longer.

The work is published in The Astrophysical Journal and funded by the National Science Foundation and NASA.