The discovery was made possible by a new planet verification method developed by astronomers at NASA's Ames Research Lab in Silicon Valley.
Kepler, the planet-hunting satellite telescope that was taken out of commission last spring, has helped discover more than 1,700 planets since it was launched in 2009.
"We've almost doubled just today the number of planets known to humanity," Jack Lissauer, a planetary scientist on the Kepler team, told reporters on Wednesday.
When in operation, Kepler used the transit method to locate planets -- a method that involves picking up on faint dips in light of faraway stars, a signal that a planet passed in front of its host star. But scientists had to use an arduous and complicated method for verifying that these dips were cause be planets and not one star eclipsing another in a binary star solar system.
Now, a new method for verification allows astronomers to more quickly eliminate the possibility of a star eclipsing another star.
"The fact that you can't have multiple star systems that look like planetary systems is the basis of verification by multiplicity," Lissauer explained. He said the breakthrough has enabled a "veritable exoplanet bonanza."
Researchers at Ames say four of the newly discovered planets could possibility host water, orbiting at just the right distance from their host stars.
Details of the discoveries are set to be published in Astrophysical Journal later this year.
The Kepler probe mission was postponed in May of 2013 after the "fine-pointing" technology that allows the satellite to focus precisely on a distant star began malfunctioning.