for National Geographic News
One of our closest stellar neighbors might host a habitable Earthlike world that could be detected by telescopes within the next few years, scientists say.
If so, it would be the closest Earth "twin" yet found and also the smallest extrasolar planet discovered so far.
Alpha Centauri B is a sunlike star that belongs to the triple-star system Alpha Centauri.
At a mere 4.35 light-years from Earth, the system is a popular destination for interstellar travel in science fiction, from Philip K. Dick to Star Trek.
"If there's an Earth-mass planet orbiting Alpha Centauri B, we'll find out about it within our lifetimes," said Greg Laughlin, an astrophysicist at the University of California, Santa Cruz (UCSC).
"It's going to be moved from the realm of science fiction into fact," added Laughlin, who is co-author of a new study modeling planet formation around the star.
(Related news: "Potentially Habitable Planets Are Common, Study Says" [February 18, 2008].)
The team's work will be detailed in an upcoming issue of The Astrophysical Journal.
One or More Earths
Laughlin and colleagues' computer model simulates potential planet formation around Alpha Centauri B over the course of 200 million years.
The program follows the merger of hundreds of moon-size "planet embryos" into full-fledged rocky planets.
The team ran the model eight times, and in every case a system of multiple planets with at least one Earthlike world evolved.
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