'New Earth' located
The ESO's rendition of the Gliese 581 solar system
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Wednesday, 25, Apr 2007 08:14
A planet outside our solar system that resembles Earth more than any other has been found.
European scientists say the exoplanet is only 50 per cent larger than Earth, with a mass five times our planet.
And, crucially, the European Southern Observatory (ESO) claims that liquid water could potentially exist on the planet, despite it being 14 times closer to its star than the Earth is to the Sun.
This is because its host star, red dwarf Gliese 581, is smaller and colder than the Sun.
A team of Swiss, French and Portuguese scientists discovered the planet using the ESO 3.6m telescope.
Gliese 581 is one of the 100 closest stars to our solar system at a distance of 20.5 light years and also harbours a Neptune-mass planet already known to astronomers.
"We have estimated that the mean temperature of this super-Earth lies between zero and 40 degrees Celsius, and water would thus be liquid," said Stephane Udry from the Geneva Observatory.
"Moreover, its radius should be only 1.5 times the Earth's radius, and models predict that the planet should be either rocky - like our Earth - or covered with oceans."
And Xavier Delfosse, a member of the astronomy team from France's Grenoble University, described the planet as a "very important target of the future space missions dedicated to the search for extra-terrestrial life".
"On the treasure map of the Universe, one would be tempted to mark this planet with an X," he added.
The discovery was made possible by the ESO's High Accuracy Radial Velocity for Planetary Searcher (Harps), a powerful spectrograph described by scientists as a "unique planet-hunting machine".
Spectrographs measure light properties over a specific portion of the electromagnetic spectrum.
The first verified discovery of an exoplanet - named 51 Pegasi b - was made in 1995 by European astronomers.