By Ron Cowen
Surveying thousands of stars for telltale twinkles that signal the passage of an orbiting planet, NASA’s Kepler spacecraft has discovered a whopping 706 candidate planets beyond the solar system. If confirmed, that motherlode would boost the number of known extrasolar planets, now estimated at 460, to well over a thousand.
The trove, announced June 15, includes evidence of five stars that have full-fledged planetary systems. These exoplanet systems, if verified, would be the first known in which each planet creates a minieclipse as it transits, or passes in front, of its parent star. The amount of dimming and the duration of a transit offer information about planets, including their size, that cannot be gleaned by less direct methods of detection.
A team including Kepler lead scientist William Borucki of NASA’s Ames Research Center in Moffett Field, Calif., has posted the findings online (at lanl.arxiv.org/abs/1006.2799 and at lanl.arxiv.org/abs/1006.2763) at arXiv.org. The discoveries were made by analyzing Kepler’s first few months of data, recorded in the spring of 2009 when the telescope examined 156,000 stars.
“This is a massively historic discovery,” says study coauthor Sara Seager, a theorist at MIT. “This is showing how the Kepler mission will revolutionize exoplanets and change the way we do exoplanet science.”