Kiwis help discover new planet 

Two New Zealand astronomers have played a crucial role in the discovery of a new planet.

It is regarded as a ground breaking result in the search for planets that could support life.

Husband and wife team, Dr Michael Albrow and Dr Karen Pollard of Canterbury University, say the discovery could also one day lead to finding a twin earth.

The planet, called OGLE-2005-BGL-390Lb, is some 25,000 light years from earth near the centre of the Milky Way, has low mass, a very low temperature and is likely to have a solid icy or rocky surface.

The planet weighs more than five times the Earth, orbits a star one-fifth the mass of the Sun and has an estimated surface temperature of -220 degrees celsius.

Albrow says finding the planet is like opening a new chapter in planetary discoveries.

"Although what we've done in no way says anything about whether life exists on this planet...it is the type of planet which could potentially support life," says Albrow.

The new planet is significantly more earth-like than any other and was just the third planet found using a new gravitational micro-lensing technique.

Microlensing occurs when a star passes in front of a background star.

The gravitational field of the foreground star acts as a lens, bending and focusing the light of the background star which brightens and then fades in a very characteristic manner.

"When you get an image we immediately analyse it to see if there's a deviation signature and if there's something there you ring up the next observer and say 'hey, you've got to watch this thing...something's happening.'" says Pollard.

The discovery has taken ten years of daily observations for 30 scientists around the world.

And it is not likely to be the end for Pollard and Albrow, who believe there are more earth-like planets waiting to be found.