Planet Hunters ; by Day, They Work in Many Fields. by Night, They Help Professional Astronomers Search for Faraway Worlds

Article excerpt

A suburban backyard nearly an hour's drive north of San Jose, Calif., might seem to be an unlikely spot for taking part in one of modern astronomy's grandest adventures.

Yet when the last faint glow of dusk vanishes from cloudless skies, Ron Bissinger is likely to head to his modest garden-shed observatory to begin his search for worlds beyond our solar system.

A software-company vice president by day, Mr. Bissinger is one of a

handful of amateurs helping to create a potentially worldwide collaboration between amateur and professional astronomers.

Their common cause is the search for planets that eclipse their parent stars. Such backlit planets can reveal characteristics that could lead to the discovery of a world beyond our sun's reach that displays evidence of organic life.

Five years ago, the notion of enlisting amateur astronomers in extrasolar planet exploration probably would have drawn snickers at an astronomy conference. The task would have been deemed too difficult for equipment available to the backyard enthusiast.

But two years ago, a team of amateurs in Finland observed the transit of a planet orbiting a star 150 light-years away in the constellation Pegasus.

Professionals sat up and took notice.

The Finnish group summarized its results in Sky and Telescope magazine in January 2001. After looking at the data, "I realized that the equipment readily available to high-end, interested, committed amateurs is more than capable of discovering these transits," says Greg Laughlin, an astronomer at the University of California at Santa Cruz and a member of a team based at UC- Berkeley credited with discovering more than 50 extrasolar planets.

For amateurs engaged in the search, the quest can be a life- altering experience.

"It's definitely not helping my sleep cycle any," Bissinger quips during a phone interview from his Pleasanton, Calif., home. "I have an 11-year-old daughter who came to me about six months ago and said, 'Dad, I've concluded that you're nocturnal.' "

Yet the prospect of participating with the pros in one of astronomy's cutting-edge fields is too alluring to pass up, he adds. "What drives me is the childlike wonder - the awe I have doing this in the shadow of some very smart, very good people."

The project, known as Transitsearch.org, began to take shape in January, spearheaded by Dr. Laughlin and Tim Castellano of NASA's Ames Research Center in Mountain View, Calif.

It comes at an opportune moment. During the past few years, concerns about the danger to Earth from comets and asteroids have triggered several government and privately funded programs to look for these objects. Some of these efforts are highly automated and take advantage of telescope optics designed for military use, leaving many amateur observers eating comet dust.

At the same time, professional astronomers have been detecting new planets beyond our solar system at an accelerating rate.

Since 1995, astronomers have detected 100 extrasolar planets. That pace is likely to accelerate, researchers say, as technology improves and researchers dedicate more telescope time to the hunt. The Berkeley team, for example, has funding to build a 1-meter- class telescope at the Lick Observatory. It will be employed full- time as a planet hunter.

Out of the first 100 extrasolar planets detected, one is known to transit its home sun. As the list of new planets grows, astronomers anticipate the number of transiting planets will grow.

Once astronomers discover a planet, however, they usually aim their telescopes at the next star on their search list.

Debra Fischer, an astronomer at the University of California at Berkeley and another member of the planet-hunting team, notes that competition for telescope time is intense. …