Astronomers spot habitable planet

LOS ANGELES - Astronomers have detected a sun-like star that hosts a planet that perhaps could support life, a study reported on Wednesday.

Located just 12 light years away, Tau Ceti has five planets about two to 6.6 times bigger than Earth. One of the planets has a mass about five times that of the Earth and lies in the star's "habitable zone" -- the right orbital distance from the star where temperature is neither too hot nor too cold for liquid water, which is essential for life, to exist on a planet's surface.

This potential habitable planet completes one lap around Tau Ceti every 168 days. If its existence is confirmed, the planet would be the smallest yet found in the habitable zone of a sun-like star, researchers said.

"This discovery is in keeping with our emerging view that virtually every star has planets, and that the galaxy must have many such potentially habitable Earth-sized planets," said the study's co-author Steve Vogt of the University of California, Santa Cruz. "They are everywhere, even right next door."

Astronomers turned up nothing when they searched for planets around Tau Ceti before. But in the new study, researchers using new analysis and modeling techniques re-filtered data from more than 6,000 observations of Tau Ceti and successfully pulled out the five faint signals from distorting "noise" caused by stellar activity and other factors.

More than 800 planets have been spotted orbiting stars outside the solar system since the 1990s. The Kepler telescope, which was launched into space in 2009, has searched more than 100,000 stars for signs of Earth-like planets in habitable zones. The telescope has so far confirmed more than 100 such planets.

Those found around stars close to us are the most interesting to astronomers.

Details of the discovery would be published in the Astronomy & Astrophysics journal.