NASA's Kepler telescope has discovered 461 potential new planets, bringing the total number of planet candidates to 2,740, orbiting 2,036 stars.

Interestingly, four of the 461 potential planets are found to be less than twice the size of Earth and are orbiting in their sun's "habitable zone," Kepler mission scientists announced Monday. A habitable zone is where water might exist on the planet's surface.

The new data, collected during observations by Kepler from May 2009 to March 2011, has revealed that the number of Earth-size and super Earth-size planet candidates has increased by 43 and 21 percent respectively.

Kepler identifies the planets by measuring the changes in the brightness of more than 150,000 stars when planets pass in front of their host star. Earth-sized planets would take 365 days to orbit their host star. Planets which are located close to their parent star would transit more often, reports Reuters.

The Kepler data also shows a significant rise in stars that have more than one planet candidate orbiting them. According to estimations by mission officials, there are 467 stars having more than one potential planet orbiting them, as against 365 detected earlier.

"The large number of multi-candidate systems being found by Kepler implies that a substantial fraction of exoplanets reside in flat multi-planet systems," Jack Lissauer, planetary scientist at NASA's Ames Research Center in Moffett Field, Calif., said in a statement.

"This is consistent with what we know about our own planetary neighborhood."

More than 13,000 transit-like signals were analyzed to identify the potential planets. Further analysis of the candidate planets need to be done to confirm them as planets.

As of today, a total of 105 candidates of the 2,740 objects are confirmed as planets.