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Tuesday, June 25, 2013

Scientists Confirm Three Potentially Habitable Planets Around A Nearby Star 06-26

Scientists Confirm Three Potentially Habitable Planets Around A Nearby Star

Alex Knapp

Astronomers from the European Space Observatory have confirmed that there are three potentially habitable worlds around the red dwarf Gliese 667C.
Scientists at the European Southern Observatory announced today that they’ve confirmed the existence of three planets existing in the habitable zone of the star Gliese 667C – meaning that they orbit at a distance from the star where temperatures might allow for liquid water on the planets’ surface. The study also found four additional planets around the star, which is part of the triple-star system Gliese 667. This system is a neighbor of ours – it’s only about 22 light years away.Astronomers had previously found three of the worlds around Gliese 667C, but finding seven planets around one stars helps to confirm that there may be plenty of stars out there with a lot of planets around them like our own Sun.
The three potentially habitable planets are considered to be “super-Earths” – meaning that they are more massive than our planet but less massive than a gas giant like Uranus. Right now, though, scientists haven’t been able to make the measurements they need to determine the composition of these planets.
Of course, there’s a catch: like most stars that astronomers have found planets on, Gliese 667C is a red dwarf, and whether life could evolve on planets orbiting red dwarves is a very open quesiton. That’s true for a number of reasons. First, because they’re so close to their stars, planets around a red dwarf may become tidally locked – meaning that they don’t rotate around their axis like the Earth does. The sun will always shine on one side of the planet and not the other. As a result, in the early years of the planet, all of the water might be “boiled off” –leaving no water to create life.
Of course, that’s one possibility. But it depends on the how thick the atmosphere is around the planets in question. The scientists conducting this research noted that at the present time, it’s impossible to tell the composition of the planets or their atmospheres. As a result, they note, “we assert that tidal locking does not preclude habitability” of the Gliese 667C planets.
There are other issues with red dwarves that might preclude habitability. Still, those are just some possible issues – and scientists have developed hypotheses about mechanisms that might allow for the evolution of life around red dwarves. Even here on Earth, scientists recently discovered tons of bacteria living in the upper atmosphere – an area where scientists expected very little life to thrive. So there may be the possibility for many kinds of interesting life to evolve on planets near red dwarves.
And it looks like we’ll have plenty of chances to explore the possibilities. As the authors conclude in their paper, the evidence they’ve found “suggests the existence of a numerous population of planetary systems with several potentially habitable worlds each. GJ 667C is likely to be among first of many of such systems that may be discovered in the forthcoming years.”
(Image: An artists conception of the planetary surface of planet Gliese 667d. Credit: ESO)