What appear to be planets still in the process of formation have been observed around a brilliant but mysterious "disc star" in the constellation Cygnus (The Swan).
The discovery was made by astronomers at the University of Arizona and the National Aeronautics and Space Administration's Ames Research Center in California. It was the first identification of such a flat, disc-shaped star that looks remarkably like what scientists believe our sun and solar system looked like 4.6 billion years ago at the time of creation.
"I think this is a spectacular step forward in the theory of star formation," the University of Arizona's Dr. Rodger I. Thompson said at the American Astronomical Society's annual meeting in Atlanta. "It's the first star we've been able to identify in its early stages of formation."
The star at the center of the disc is about 10 times the size of our sun and is located 10,000 light years away, which means the light reaching us left the star 10,000 years ago. Astronomers believe the star's light we are seeing is only 1,000 years old, which makes the star quite young.
Bright concentric rings of luminous gas circle the star and extend out about 4 billion miles from the star's surface. It is along the edges of these rings that astronomers think planets are being formed, as the gas and dust not being drawn into the star cool outside the hottest part of the disc near the star.
Temperatures at the edge of the star are believed to be about 35,000 degrees Fahrenheit, about seven times hotter than our sun. This is one reason scientists believe the star to be no more than 1,000 years old. Stars are hottest when young.
The star was first found 40 years ago by British astronomers, who were puzzled that it appeared to be too bright for a star its size. What the Arizona and Ames astronomers have done, using infrared telescopes, is to find and identify the bright gas discs circling the star.
The discs emit about 10 times as much light as the star but are losing about 1 to 2 per cent of their light each month. This is why scientists believe planets are being formed in the discs. The light of the discs is thought to be fading as the gas and dust condense, which is how planets would be formed in any solar system.
At the rate the disc are losing light, they will be gone in about 100 years. The star is at the center of the discs is expected to live for only 100 million years, at which time the nuclear fuel creating its light and heat will be exhausted.