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First planet reported outside solar system

By
AL ROSSITER JR., UPI Science Editor

WASHINGTON -- Astronomers in Arizona have discovered what appears to be a giant ball of hot gas orbiting a distant star, which would make it the first planet observed beyond our solar system, the National Science Foundation announced Monday.

The government research agency said a team led by Dr. Donald McCarthy Jr. of the University of Arizona used a new technique to detect heat radiation from the apparent planet around the star Van Biesbroeck 8, which is 21 light years from Earth.

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McCarthy and associates calculated the object to be 30 to 80 times more massive than Jupiter, the largest of the nine planets circling the sun. They estimated the outermost temperature of its gases is about 2,000 degrees F -- hotter than any of the sun's planets, but too cool to be a star.

The apparent planet shows up in powerful telescopes as a point of infrared light next to the star. McCarthy said in a telephone interview he has no doubt that the object is orbiting Van Biesbroeck 8 and is not some more distant background object.

He said other researchers will want to verify the finding before it can be accepted as the first planet beyond the solar system.

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Scientists have long assumed planet-sized objects revolve around other stars. A NASA satellite has detected a cloud of matter around the star Vega and two astronomers recently photographed a vast swarm of particles around a star 50 light years away, but they were not able to detect any planet-sized bodies.

The existence of planets beyond the sun's system is a basic assumption of researchers who speculate on the existence of extraterrestrial life. They theorize that some planets around far-off suns must have conditions similar to those under which life evolved on Earth.

'A necessary first step is that you show there are planets around other stars,' McCarthy said.

'This one is certainly not a habitable planet and the star it is going around is not very hot like our sun so there probably isn't any life there. But it is a step in the direction that should lead to the discovery of systems of planets around other stars.'

The star Van Biesbroeck 8, located in the Milky Way constellation Ophiuchus, is only about 10 percent as massive as the sun, with a temperature of about 3,000 degrees F, McCarthy said. The sun has a temperature of 9,900 degress F.

McCarthy said Van Biesbroeck 8's companion object is not much smaller, but is below the size necessary to sustain the thermonuclear reaction of a star.

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Additional research is needed to determine the precise mass of the planetary object and its makeup, he said.

The object was detected with the use of a technique called infrared speckle interferometry using the 158-inch Mayall Telescope at the Kitt Peak National Observatory and the 90-inch telescope at the university's Steward Observatory.

The finding has been submitted to Astrophysical Journal Letters for publication.

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