The newly verified planets orbit 305 stars, revealing multiple-planet systems like the Earth’s solar system.
The discovery marks a significant increase in the number of known small-sized planets more like Earth than previously identified planets outside of the solar system, according to the space exploration agency.
"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,” said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington.
Launched in March 2009, Kepler is the first NASA mission to find potentially habitable Earth-size planets.
In order to verify the existence of the new planets, scientists used a statistical technique called verification by multiplicity that can be applied to many planets that harbor around the same star at once rather than verify each one individually.
The verification process was conducted by a research team co-led by Jack Lissauer, planetary scientist at NASA's Ames Research Center in Moffett Field, California.
The team uses a photometer to observe 150,000 stars, and of those, found a few thousand with more than one potential planet, observed between the first two years of Kepler’s observations from May 2009 to March 2011.
Of the sample studied, 715 new planets were verified.
"Four years ago, Kepler began a string of announcements of first hundreds, then thousands, of planet candidates -- but they were only candidate worlds," said Lissauer. "We've now developed a process to verify multiple planet candidates in bulk to deliver planets wholesale, and have used it to unveil a veritable bonanza of new worlds."
This latest discovery brings the confirmed count of planets outside the solar system to nearly 1,700.
“These multiple-planet systems are fertile grounds for studying individual planets and the configuration of planetary neighborhoods,” the agency said in a press release. “This provides clues to planet formation.”
-- Sameea Kamal, firstname.lastname@example.org
Follow on Twitter: @SameeaKamal.