Article Posted on : - Mar 19, 2010

WASHINGTON (PTI): A Jupiter-size planet has been discovered beyond the solar system nearly 1,500 light years away by a French spacecraft.

The spacecraft designed to discover new worlds has made one of its most significant finds yet -- COROT 9 b -- a planet that looks like a cousin to those in our own celestial backyard, journal Nature reported.

The planet is less massive than Jupiter and orbits a star; called COROT 9, at about the same distance Mercury orbits the sun.

The new world is of fairly average size, but it is the most temperate exoplanet yet whose properties are well known in orbit around a sunlike star, said lead study author Hans Deeg, an astronomer at Spain's Institute of Astrophysics of the Canary Islands.

Residing 1,500 light-years away in the constellation Serpens Cauda, COROT 9 b has about the same diameter as Jupiter and is about 85 per cent as massive.

It keeps a much greater distance from its host star than the other transiting planets discovered to date, almost all of which reside in scalding hot orbits less than 10 million kilometres from their stars, scientific American said.

The newfound world circles its star at about 60 million kilometres, leaving it with a relatively mild temperature that Deeg's group estimates to be between minus 20 degrees Celsius and 150 degrees C, depending on its atmospheric makeup.

For comparison, many exoplanets are so close to their stars that their temperatures exceed 1,000 degrees C.