Smallest extrasolar planet discovered

MADRID (AFP) - Spanish astronomers Wednesday announced the discovery of
the smallest planet discovered to date outside the solar system,
located 30 light years from earth.

The planet, "GJ 436T", was detected through a new technique which "will
allow us to discover in less than 10 years the first planet resembling
earth in terms of mass and orbit," said Ignasi Ribas of Spain's CSIC scientific research institute.

It was discovered by a team led by Ribas through its gravitational pull
on other planets already discovered around the same star in the
constellation of Leo.

"GJ 436T" has a mass five times the size of Earth, which makes it the
smallest extrasolar planet among the roughly 300 identified so far,
Ribas said in announcing the discovery.
He said the new planet is uninhabitable due to the distance that
separates it from its star, which is far less than that between the
earth and the sun.

To sustain life, a planet must have a mass similar to that of earth,
liquid water on its surface, an atmosphere and a similar orbital
distance from its star as that of the earth from the sun.

Initial calculations by the team indicated that "GJ 436T" rotates in 4.2 earth days and orbits its star every 5.2 days.

http://news.yahoo.com/s/afp/20080409/sc_afp/spaceastronomyplanets_080409190123