NASA's Kepler Mission Has Discovered 715 New Exoplanets

Lee Rannals for redOrbit.com – Your Universe Online

NASA announced on Wednesday that its Kepler mission has discovered 715 new planets orbiting 305 stars.

The space agency said that 95 percent of the newly discovered worlds are smaller than Neptune, which is about four times the size of Earth. NASA added that this discovery marks an increase in the number of known small-sized planets that are similar to Earth than any previously identified exoplanets.

“The Kepler team continues to amaze and excite us with their planet hunting results,” John Grunsfeld, associate administrator for NASA’s Science Mission Directorate in Washington, said in a statement. “That these new planets and solar systems look somewhat like our own, portends a great future when we have the James Webb Space Telescope in space to characterize the new worlds.”

Researchers analyzed stars with more than one potential planet to help verify the new planets. All of the systems were detected in the first two years of Kepler’s observations from May 2009 to March 2011.

The team used a technique known as verification by multiplicity, which uses logic and probability to help find the planets. NASA said Kepler looks at 150,000 stars and found a few thousand of those stars have planet candidates, some of which have multiple planet candidates.

Four of the planets discovered are less than 2.5 times the size of Earth and orbit in their sun’s habitable zone, which is the distance from its star required for liquid water to exist. One of the habitable planets, known as Kepler-296f, orbits a star half the size and five percent as bright as our sun. Kepler-296f is about twice the size of Earth, but it is unknown if the planet is gaseous like our outer gas giants or if its watery like our own planet.

“From this study we learn planets in these multi-systems are small and their orbits are flat and circular — resembling pancakes — not your classical view of an atom,” Jason Rowe, research scientist at the SETI Institute in Mountain View, Calif., and co-leader of the research, said in a statement. “The more we explore the more we find familiar traces of ourselves amongst the stars that remind us of home.”

NASA compared the way these planets are being found to the behavior observed with lions and lionesses.

“In our imaginary savannah, the lions are the Kepler stars and the lionesses are the planet candidates. The lionesses would sometimes be observed grouped together whereas lions tend to roam on their own. If you see two lions it could be a lion and a lioness or it could be two lions. But if more than two large felines are gathered, then it is very likely to be a lion and his pride. Thus, through multiplicity the lioness can be reliably identified in much the same way multiple planet candidates can be found around the same star,” the space agency said.