UH astronomers find
pre-planet dust rings

A Big Isle telescope collects clues
to how solar systems form

Many young stars in the Orion Nebula are surrounded by enough orbiting dust and material to form a whole new planetary system like our own, University of Hawaii scientists report in an article that appears today in the Astrophysical Journal.

Lead author of the paper, Jonathan Williams of the University of Hawaii Institute for Astronomy, said yesterday that the Mauna Kea telescope on the Big Island, known as the Submillimeter Array, "is the only telescope that can measure the dust around these stars and thereby assess their true potential for forming planets."

Williams said, "The exceptional skies and the unique, cutting-edge telescopes of Mauna Kea made these observations possible and allow us to continue the quest to understand our origins."

Williams worked in collaboration with David Wilner of the Harvard-Smithsonian Center for Astrophysics.

Orbiting "pancake-shaped" dust disks, believed to be the raw material for planet formation, were first detected as misshapen silhouettes by Rice University astronomer Robert O'Dell with the Hubble Space Telescope in 1992 as they swirled around stars in the Orion Nebula, a region about 1,500 light-years from Earth where new stars are being formed.

Sean Andrews, a UH graduate student and co-author of the Astrophysical Journal, said, "The Hubble telescope showed us the size of the disks but not how much material they contained."

The theory that Earth and other planets of the solar system were formed out of such disks about 4.5 billion years ago by the coalescing of matter caused by gravitational activity is widely accepted among astronomers. O'Dell said in 1992 that the disks in the Orion Nebula presumably contain the same materials that comprise the planets of Earth's solar system, including carbon and silicates.

The dusk disks are considered a missing link in the understanding of how planets like those in our own solar system are formed. O'Dell dubbed the disks "proplyds," short for "protoplanetary disks," on the assumption that they consisted of a newly found star surrounded by a disk of matter out of which new planets are forming. They are among the youngest stars in the galaxy and were "born out of the original cold, dark cloud of gas about a million years ago," according a press statement.

A UH statement said that within the Orion Nebula, where winds can reach 2 million mph and temperatures can exceed 18,000 degrees Fahrenheit, the key question was, "Would enough material endure to form a new solar system, or would it be eroded away into space like wind and sand eroding away desert cliffs? It now appears that these protoplanetary disks are quite tenacious, bringing new grounds for optimism in the search for planetary systems."

The statement also said, "Since most sunlike stars in our Milky Way galaxy eventually form in environments like the Orion Nebula, the SMA (telescope) results suggest that the formation of solar systems like our own is common and a continuing event in the galaxy."