The Kepler mission’s science team announced its latest finding at a press conference on Monday, Dec. 5, 2011. The team announced the confirmation of Kepler-22b, its first planet found in the “habitable zone,” the region where liquid water could exist on a planet’s surface. The planet is about 2.4 times the radius of Earth, orbits around a star similar to our sun and is located 600 light-years away. Scientists don’t yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets. The planet’s host star belongs to the same class as our sun, called G-type, although it is slightly smaller and cooler.
Kepler also has discovered 1,094 new planet candidates, nearly doubling its previously known count. Since the last catalog was released in February, the number of planet candidates identified by Kepler has increased by 89 percent and now totals 2,326. Of these, 207 are approximately Earth-size, 680 are super Earth-size, 1,181 are Neptune-size, 203 are Jupiter-size and 55 are larger than Jupiter. The findings, based on observations conducted May 2009 to September 2010, show a dramatic increase in the numbers of smaller-size planet candidates.