It is the biggest planet haul yet.
NASA announced today the discovery of 715 new exo-planets orbiting 305 star systems, bringing the total number of confirmed worlds outside of our solar system to almost 1,700.
The announcement is based on findings from data gathered during the first two years of the Kepler Space Telescope’s four year survey of a tiny swath of sky containing 160,000 stars. What is particularly compelling regarding the new findings is the fact that 94% of the new confirmed planets are the size of Neptune or smaller, with a large number in the Earth or Super Earth category. Most of the planets announced today are in tightly compacted solar systems orbiting in short periods around their stars.
Because these results are based on the first two years of observations, and Kepler uses the transit technique which measures the miniscule drop in a star’s brightness as a planet passes in front of it, it is quite likely that further analysis will reveal more planets in further orbits around the same systems.
Nevertheless, four of the 715 planets announced today are orbiting within the habitable zones of their stars.
The Kepler Space Telescope is still operational, but it is not actively being used, having lost two of its four reaction wheels, making it impossible to mainatin a steady lock to use its instruments. Kepler managers are currently testing an innovative technique which would see the pressure of sunlight, combined with the two remaining wheels, used to “keep the camera” steady and subject stars in focus. The extended mission, called “K2” is awaiting approval.