June 15, 2005 — A sample survey of dusty disks in the Orion Nebula show enough material for planets to be formed, a discovery that bolsters the theory that stars with planetary systems are far from unique.

Astronomers have known that such protoplanetary disks exist in Orion's hot stellar nursery, the Trapezium.

But they were not sure how much planet-building material would remain after being blasted by ionizing radiation from the two million-mile per hour stellar winds and searing, 18,000° Fahrenheit temperatures found in the Nebula.

Researchers estimate about one-100th the mass of our sun, or enough material for 10 Jupiter-sized planets, would be needed for a planetary system to form, according to David Wilner, with the Harvard-Smithsonian Center for Astrophysics.

"All previous observations show these disks, but there was no way to determine if there was enough matter to form a solar system like our own," Wilner said in an interview.

Using a network of eight telescopes on Mauna Kea, Hawaii, that are extremely sensitive to radiation, researchers were able to determine the mass of 20 dusty disks near the Trapezium region, a cluster of more than 1,000 hot, young stars that are only about a million years old.

The stars condensed from an original cold, dark cloud of gas that is now glowing from the stars' radiation.

The Submillimeter Array is sensitive to radiation between the infrared and microwave wavelengths of the electromagnetic spectrum. Visual imagers, like the Hubble Space Telescope, show only the outer edge of the disk.

"The array is the only telescope that can measure the dust within the Orion proplyds (planetary disks)," said lead researcher Jonathan Williams, with the University of Hawaii's Institute for Astronomy. "This is critical in our understanding of how solar systems form in hostile regions of space."

Some of the disks studied appear to be similar in size and mass to our solar system, a finding that suggests that solar systems, like our own, are common and ongoing.

"These results bolster the theory that most stars are capable of supporting planetary systems like ours," Wilner said.

"You couldn't have predicted this," he added. "At least some of these objects retain enough material to form planetary systems."

In addition to adding to the survey — Orion has hundreds of planetary disks — the astronomers will attempt to further analyze the 20 disks already studied in hopes of determining if planetary formation already is under way in any of the systems.

The scientists presented their findings at a Submillimeter Array users conference this week in Cambridge, Mass.