NASA’s Kepler mission announced Wednesday it had discovered an additional 715 planets orbiting a total of 305 stars, “revealing multiple-planet systems much like our own solar system.”
The newly verified discoveries bring the total of known planets outside this solar system to 1,700, NASA said. Prior to Wednesday, the Kepler Mission had confirmed 246 planets.
Of the newfound planets, NASA said that four are less than 2.5 times the size of Earth and orbit in the “habitable zone, defined as the range of distance from a star where the surface temperature of an orbiting planet may be suitable for life-giving liquid water.”
NASA’s Kepler spacecraft, equipped with a telescope 4.7 meters long, was launched in March 2009. Kepler surveyed the Cygnus and Lyra constellations of the Milky Way, home to more 150,000 stars, in an attempt to discover Earth-sized planets orbiting in the habitable zones of various suns. In addition to the 961 planets discovered before Wednesday’s announcement, NASA data had identified more than 3,600 planet candidates. The first planets outside the solar system were discovered in the 1990s.
According a NASA video explaining the discovery, “Kepler works by looking for the slight dimming of starlight caused when a distant planet transits its parent star.” When the Kepler team notices a dip in stellar brightness, it could be caused by the orbits of planets, thus the “planet candidate” designation.
NASA also credited a research team at the Ames Research Center in Moffett Field, Calif., led by planetary scientist Jack Lissauer. The team used a technique called “verification by multiplicity,” which relies, in part, on the logic of probability as it applies to random distribution.
“Four years ago, Kepler began a string of announcements of first hundreds, then thousands, of planet candidates –but they were only candidate worlds,” Lissauer said. “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.”
The findings come from data captured between 2009 and 2011, NASA said.
The Kepler telescope had its pointing ability compromised in 2013, leading to a repurposing of the spacecraft. In January, project scientists put forward a proposal known as K2, which spacenews.com said would shift the observations “from a narrow swath of sky to five or six fields of view aligned roughly with Earth’s orbit, or ecliptic plane. In the K2 configuration, Kepler would scan one field of view for 80 days before beaming data back to Earth.”
The findings will be published March 10 in The Astrophysical Journal and are available for downloading here.
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