NASA's Kepler mission discovers over 1,200 new planets

 In the largest finding of planets to date, NASA has announced the discovery of 1,284 new planets outside our solar system, more than doubling the number of exoplanets found by the Kepler space telescope

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Nine of the newly found planets may be potentially habitable, NASA said.
"This gives us hope that somewhere out there, around a star much like ours, we can eventually discover another Earth," said Ellen Stofan, chief scientist at NASA Headquarters in Washington.

"This announcement more than doubles the number of confirmed planets from Kepler," said Stofan.

Analysis was performed on the Kepler space telescope's July 2015 planet candidate catalogue, which identified 4,302 potential planets.

For 1,284 of the candidates, the probability of being a planet is greater than 99 per cent - the minimum required to earn the status of "planet".

An additional 1,327 candidates are more likely than not to be actual planets, but they do not meet the 99 per cent threshold and will require additional study.

The remaining 707 are more likely to be some other astrophysical phenomena. This analysis also validated 984 candidates previously verified by other techniques.

"Before the Kepler space telescope launched, we did not know whether exoplanets were rare or common in the galaxy," said Paul Hertz, Astrophysics Division director at NASA.

"Thanks to Kepler and the research community, we now know there could be more planets than stars," said Hertz.

"This knowledge informs the future missions that are needed to take us ever-closer to finding out whether we are alone in the universe," he said.

Kepler captures the discrete signals of distant planets - decreases in brightness that occur when planets pass in front of, or transit, their stars.

Since the discovery of the first planets outside our solar system more than two decades ago, researchers have resorted to a one-by-one process of verifying suspected planets.

The latest findings are based on a new method that can be applied to many planet candidates simultaneously.

In the newly-validated batch of planets, nearly 550 could be rocky planets like Earth, based on their size.

Nine of these orbit in their sun's habitable zone, which is the distance from a star where orbiting planets can have surface temperatures that allow liquid water to pool.

With the addition of these nine, 21 exoplanets now are known to be members of this exclusive group.

"This work will help Kepler reach its full potential by yielding a deeper understanding of the number of stars that harbour potentially habitable, Earth-size planets - a number that's needed to design future missions to search for habitable environments and living worlds," said Natalie Batalha, Kepler mission scientist at NASA.

Of the nearly 5,000 total planet candidates found to date, more than 3,200 now have been verified, and 2,325 of these were discovered by Kepler.