Monday, March 10, 2008

Nearest Stellar Neighbor May Have Earth's Twin

via ScienceDaily, a new mathematical model of the formation of our nearest stellar neighbor Alpha Centauri shows a rather intriguing result - the formation of a terrestrial type planet in the habital zone of Alpha Centauri B. The system has long thought to be a likely candidate for such planets, given the relatively high heavy element content of its three stars.

"The closest stars to our Sun are in the three-star system called Alpha Centauri, a popular destination for interstellar travel in works of science fiction. UCSC graduate student Javiera Guedes used computer simulations of planet formation to show that terrestrial planets are likely to have formed around the star Alpha Centauri B and to be orbiting in the "habitable zone" where liquid water can exist on the planet's surface. The researchers then showed that such planets could be observed using a dedicated telescope."

The simulations of Alpha Centauri's formation were run numerous times by a team at the University of California Santa Clara, evolving the system up to an age of around 200 million years. Although the results differed with changing assumptions run in each model, in every case simulated a system of multiple planets with at least one Earth sized planet developed. In many of these simulations, such a terrestrial planet formed in the star's habital zone, where temperatures would allow liquid water to reside.

While the star's relatively high position in the Southern sky and brightness are positive factors in finding such a planet, the gravitational "wobble" created on the star by such a planet would be quite small, and up to five years of direct observation might be necessary in order to detect a planet with current methods. There is a team out of San Francisco State University conducting such observations.

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