Tuesday, June 14, 2005

Earth-like Planet Discovered Orbiting Nearby Star

A planet that may be Earth-like — but too hot for life as we know it — has been discovered orbiting a nearby star. "This is the smallest extrasolar planet yet detected and the first of a new class of rocky terrestrial planets," Paul Butler of the Carnegie Institution in Washington said in a statement. Though the researchers have no direct proof that the new planet is rocky, its mass means it is not a giant gas planet like Jupiter, they said. They estimated the planet's mass as 5.9 to 7.5 times that of Earth. Gliese 876 is a small, red star with about one-third the mass of the sun. The researchers said this is the smallest star around which planets have been discovered. In addition to the newly found planet the star has two large gas planets around it. Butler said the researchers think that the most probable composition of the planet is similar to inner planets of this solar system — a nickel/iron rock. Gregory Laughlin of the Lick Observatory said a planet of this mass could have enough gravity to hold onto an atmosphere. Three other extrasolar planets believed to be of rocky composition have been reported, but they orbit a pulsar — the flashing corpse of an exploded star — rather than a normal type of star.

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