January 8, 2013
Kepler Data Reveals Hundreds Of New Planet Candidates
Brett Smith for redOrbit.com - Your Universe Online
After completing a new analysis of data from the Kepler space observatory, NASA scientists announced that they have identified 461 new planet candidates – including four that closely mirror the size and distance from their sun as Earth.
Kepler´s mission to find Earth-like planets was recently extended to 2016 after difficulties arose in processing the large volume of data produced by the orbiting observatory. Since the most recent release of Kepler data in February 2012, the number of planet candidates sifted from the Kepler data has grown by 20 percent to over 2,700 possible planets orbiting 2,036 stars.
"There is no better way to kick off the start of the Kepler extended mission than to discover more possible outposts on the frontier of potentially life-bearing worlds," said Christopher Burke, Kepler scientist at the SETI Institute in Mountain View, Calif., who lead the new analysis of the data.
Evidence of potential planets from Kepler´s on-board telescope was analyzed by measuring the change in brightness of more than 150,000 stars. As planets pass in front of their host star they alter its solar radiation, which is recorded by the telescope. According to NASA scientists, at least three passes are required to authenticate a potential planet.
Of the 150,000 stars that were observed, the scientists analyzed over 13,000 transit-like signals to eliminate known spacecraft instrumentation and other false positives that could be interpreted as planetary candidates.
"There is a list of astrophysical configurations that can mimic planet signals, but altogether, they can only account for one-tenth of the huge number of Kepler candidates. All the other signals are bona-fide planets," said Francois Fressin, of the Harvard-Smithsonian Center for Astrophysics.
After scrutinizing the candidates, the potential planets were divided into five different sizes: Earth-size (0.8 - 1.25 times the size of our planet), Super Earth-size (1.25 - 2 times the size of Earth), Neptune-size (2 - 4 times Earth), Jupiter-Size (6-15 times the size of Earth), and Larger (greater than 15 times the size of Earth).
The researchers expanded the number of Earth-sized candidates by 43 percent and super Earth-size candidates grew by 21 percent. The new data analysis also increased the number of stars with more than one planet candidate from 365 to 467, making 43 percent of planet candidates´ neighbors with other planets.
"The large number of multi-candidate systems being found by Kepler implies that a substantial fraction of exoplanets reside in flat multi-planet systems," said Jack Lissauer, planetary scientist at NASA's Ames Research Center in Moffett Field, Calif. "This is consistent with what we know about our own planetary neighborhood."
The Kepler data was also analyzed to show how far these potential planets orbit their sun. A planet found to be in an Earth-like orbit would present the ideal conditions for liquid water, a key building block for life as we know it.
"The analysis of increasingly longer time periods of Kepler data uncovers smaller planets in longer period orbits-- orbital periods similar to Earth's," said Steve Howell, Kepler mission project scientist at Ames. "It is no longer a question of will we find a true Earth analogue, but a question of when."