From Sciences Online Daily News Site

摘要

Astronomers operating the Kepler telescope orbiting the sun in Earth's wake have discovered an extrasolar planet not much larger than Earth—the smallest exoplanet yet found. The telescope stared for months on end at the same 150,000 stars in the constellation Cygnus looking for the telltale dimming of a star as a planet passes in front of it. One star, 560 light-years away and designated Kepler-10, dimmed 0.015% every 0.84 days, indicating a planet, dubbed Kepler-lOb, orbit- ing 20 times closer to its star than Mercury orbits the sun. The planet has a diameter 1.42 times Earth's and a density 8.8 times Earth's, and local temperatures are a blazing 1833 K, the team announced this week at the winter meeting of the American Astronomical Society in Seattle, Washington. It's improbable that such a planet could harbor life, but with this milestone behind them, the Kepler team could be announcing the discovery of an Earth-like, habitable exoplanet within a few years.