

Researchers at the University of California have developed a computer model of the triple star system at Alpha Centauri that shows that Alpha Centauri B (the largest of the three stars) could have rocky Earth-like planets orbiting within its habitable zone, where liquid water could exist.

At four light years away, these are the closest stars to our solar system. Of the 276 extrasolar planets we have found so far none of them have been that local. Now two of the co-authors are about to start a campaign at Cerro Tololo Observatory in Chile to observe Alpha Centauri to test methods to look for these planets.

Alpha Centauri is a good target because, like the Big Dipper in the Northern Hemisphere, Alpha Centauri is almost always up in the Southern Hemisphere night sky for observing. Being so bright and nearby would also help researchers detect the tiny wobble a small terrestrial planet would impart.

Scientific modeling of solar system formation had previously found that while gas giants are unlikely to form in the Alpha Centauri system, rocky planets would. This new data that the possible planets could be in a habitable zone makes it all the more tantalizing.

University of California researcher Javiera Guedes developed the simulations of the system's first 200 million years.

In each instance, despite different parameters, multiple terrestrial planets formed around the star. In every case, at least one planet turned up similar in size to the Earth, and in many cases this planet fell within the star's habitable zone.

Co-author and Professor Gregory Laughlin said, "We're advocating that there's a strong possibility a planet could be there."

Study co-author Debra Fischer of San Francisco State University is leading the NSF funded program on the 1.5-meter telescope at the Cerro Tololo Inter-American Observatory to monitor Alpha Centauri A and B, Tau Ceti, GJ780 and Beta Hydri through November 2009. The team says that a dedicated five year campaign should be able to discern the presence of even an Earth sized rocky planet.

If Alpha Centauri Has Earth-like Planets, We Can Detect Them [Universe Today]

Nearest Star System Could Harbour Earth Twin [Space.com]

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Image: NASA