Super-earth exoplanet found that could support life

Astronomers find a second planet outside our solar system which is the right distance from its star for life to exist

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• Hannah Godfrey
• guardian.co.uk, Tuesday 13 September 2011 01.20 BST
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Our planet Earth. Astronomers have found a super-earth exoplanet 37 light years away from our solar system. Photograph: Anonymous/AP
Astronomers say they have found a second planet outside our solar system that is the right distance from its star to potentially support life. But any possible inhabitants would need to have a taste for an environment that felt like a hot steam bath. European astronomers announced the discovery of a total of 50 planets outside our solar system. Among these was one which lies in the "Goldilocks zone" – an area which is neither too hot nor too cold for liquid water, an essential for Earth-like life, to be present. The only past discovery of a Goldilocks planet that still stands up today is one that was found in 2007. To be able to support life the new planet would need not only to have water, it would also need to be solid, like earth and not made up primarily of gas, like Jupiter. The newly discovered planet, which is called HD85512b, is about 3.6 times the mass of Earth, it is estimated that temperatures there range from 30C to 50C, and it is thought that the atmosphere is very humid. "It's going to be really muggy, just think about the muggiest (Washington) day you can think of," said Lisa Kaltenegger, an astronomer with the Max Planck Institute in Germany, and author of the new study. "We're not saying it's habitable for you and me." But other types of life – probably shorter and squatter – could conceivably take root there, she said. They would probably be closer to the ground than humans because gravity on the planet is about 1.4 times what we experience. According to Kaltenegger, at least 60% of the planet would need to be covered in cloud for it to be potentially habitable. Earth has about 50% cloud cover. HD85512b closely circles a star about 35 light years from Earth in the constellation Vela. Each light year is 5.8 trillion miles. A year on the planet is only 60 days. Its sun is about 1,000C cooler than our sun. The new "exoplanets" were found by the European Southern Observatory's special planet-hunting instrument called Harps, which is based in Chile. The finding doubles the number of planets that are closer to Earth in mass than those closer to Jupiter's size. This new Goldilocks planet was observed more than a thousand times over 200 nights of tracking from Chile so astronomers are confident of their findings, said study author Francesco Pepe of the Geneva Observatory in Switzerland. In addition to the two European discoveries of potentially habitable planets, a Nasa telescope has identified more than 50 other candidates, but those still need further investigation.