Europe discovers over thirty new exoplanets

AFP - Astronomers announced Monday the discovery of 32 new planets outside our solar system, some of them only a few times larger than Earth.

The relatively small size increases the odds that these so-called exoplanets could have conditions similar to the ones that gave rise to life on Earth.

Scientists made the finds using the High Accuracy Radial Velocity Planet Searcher, or HARPS, the most successful low-mass exoplanet hunter in the world.

The HARPS spectrograph is attached to the European Southern Observatory's (ESO) 3.6-metre telescope at La Silla, Chile.

The findings, presented at an exoplanet conference in Porto, Portugal, raises the number of known exoplanets to more than 400, a fifth of them -- from 30 different planetary systems -- uncovered by HARPS.

Most are giant balls of toxic gas similar to Jupiter, and thus would be inhospitable to life as we know it.

But 28 are so-called "super-Earths" with masses 20 times the size of Earth or less, and are thus probably rocky planets, the ESO said in a press release.

Whether any harbour carbon-based life forms would depend in part where they orbit in relation to their stars.

Earth sits in a so-called "Goldilocks zone" where the temperature is neither too hot for our atmosphere to be stripped away, nor too cold for our seas to freeze -- but just right to have liquid water, the stuff of life.

HARPS was designed and built by a team from the Geneva Observatory led by Michel Mayor, who unveiled their most recent findings.

"We have now completed our initial five-year programme, which has succeeded well beyond our expectations," Stephane Udry, a researcher at the University of Geneva, said in a statement.

No Earth-like planets were discovered in the group that was announced Monday, he said.

As with the previously detected super-Earths, most of the new low-mass candidates reside in multi-planet systems, with up to five planets per system.

Distant planets, even big ones, are too small to be directly observed, and can only be detected by measuring their impact on the movement of the stars they orbit.

The first exoplanet discovered -- 51 Pegasi b -- was found in 1995, and the first super-Earth came to light in 2004.

Gliese 581e, the lightest exoplanet so far detected around a normal star, was spotted earlier this year.

Planets are formed from a disc of gas and dusty debris left over from the creation of a star. Just how long this process takes is still a matter of debate.

Earth is believed to be about 4.5 billion years old, and the Sun about 500 million years older.