Astronomers claim biggest haul of other worlds

London - 13 Sep 2011 (AFP): Astronomers on Tuesday unveiled a haul of more than 50 planets orbiting other stars, including a "super-Earth" which inhabits a zone where, providing conditions are right, water could exist in liquid form.

It is the biggest single tally in the history of exoplanet hunting since the very first world beyond the Solar System was spotted in 1995, the European Southern Observatory (ESO) said in a press release.

The planets were detected using a light analyser, or spectrograph, on a 3.6-metre (11.7-feet) telescope at La Silla Observatory in the ultra-dry conditions of Chile's Atacama desert.

The findings were presented at a conference on Extreme Solar Systems in Moran, Wyoming, attended by 350 exoplanet specialists.

Sixteen of the planets have been designated "super-Earths", a term meaning that they are exceptionally small for exoplanets that have been spotted so far.

A super-Earth is between one and 10 times the mass of the Earth. It does not necessarily mean that the world is rocky -- as opposed to gassy -- or that the conditions for life exist.

However, one of the 16 new "super-Earths", called HD 85512 b, which is estimated to be only 3.6 times the mass of the Earth, is orbiting at an intriguingly promising distance from its star.

It is just at the far edge of the so-called Goldilocks zone, where the temperature should be balmy enough for water, the stuff of life as we know it, to exist in liquid form rather than as ice or a gas.

The sighting is not a confirmation that HD 85512 b is a habitable planet, but should be seen as a technical advance for determining if other potential homes-from-home exist, ESO said.

Nearly 600 exoplanets have been detected since 1995, but none has looked remotely like Earth. Many are gas giants that orbit so close to their sun that their atmospheres are scorching.

"In the coming 10 to 20 years, we should have the first list of potentially habitable planets in the Sun's neighbourhood," said Michel Mayor, a University of Geneva astronomer who discovered the first-ever exoplanet, and led the ESO team.

"Making such a list is essential before future experiments can search for possible spectroscopic signatures of life in the exoplanet atmospheres."