NASA’s Kepler finds 68 new Earth-size planet candidates

NASA’s Kepler Mission revealed data this week detailing the discovery of 68 new Earth-size planet candidates, 54 of which are in the habitable zone, a region around a star where liquid water could exist on a planet’s surface. This is the first discovery of Earth-size planet candidates in the habitable zone.



“In one generation we have gone from extraterrestrial planets being a mainstay of science fiction, to the present, where Kepler has helped turn science fiction into today’s reality,” NASA Administrator Charles Bolden said in a press release. “These discoveries underscore the importance of NASA’s science missions, which consistently increase understanding of our place in the cosmos.”

The Kepler mission’s principal investigator Bill Borucki said the mission’s biggest discoveries were finding the 54 planet candidates in the habitable zone of other stars, as well as finding that about 17 percent of the stars have multiple candidate systems.



“They have systems of planets, like our solar system,” he said. “There’s not just one planet, but there’s a group of them with different characteristics and different positions.”



This is the first discovery of such planet candidates, uncovered in data the Kepler mission collected in its first four months of operation, from May 12 to Sept. 17, 2009.

Borucki said now that astronomers have a good idea of the frequency of Earth-size planet candidates in the habitable zone, they need to build the next major instruments to go and find their atmospheres.



Kepler also discovered six confirmed planets orbiting a yellow dwarf star similar to the sun, called Kepler-11. All of the six planets orbiting Kepler-11 are larger than Earth, and five of them are closer to the dwarf star than any planet is to our sun.



“This is the most compact planetary system discovered by any means,” said Jack Lissauer, a Kepler scientist and co-investigator who is the lead investigator for the Kepler-11 planet system. “It shows that you can have planets orbiting close to one another. That means there’s potential for there to be other systems that might have several planets in the habitable zone.”



The Kepler’s latest data are based on observations of more than 156,000 stars in Kepler’s field of view, accounting for about 1/400 of the sky.



Borucki said that if you compared the Hubble Space Telescope’s field of view to the size of a grain of sand, the Kepler Space Telescope’s field of view is about the size of a fist.


“The Hubble looks at one little area with a great deal of resolution,” Borucki said. “We look at a much larger area, but our images are fuzzy — and they must be to measure the brightness of the stars.”

To date, the Kepler mission has uncovered 1,235 total planet candidates. To verify these are actually planets, the candidates require follow-up observations.


“This bodes well for Kepler’s discovery in the future,” Lissauer said. “We’ve been able to find something that was really, totally unexpected, and this was just the first part of the mission.”



The Kepler spacecraft is about halfway through its mission and will continue searching for planets until at least November 2012.




Credits -http://news.medill.northwestern.edu/chicago/news.aspx?id=177894