The Kepler planet-finding mission’s first rocky planet, announced in February, has a similarly-sized sibling, the team announced at the American Astronomical Society conference in Boston today. The discovery – dubbed Kepler 10C, is the first planet to be confirmed using infrared data from NASA’s Spitzer Space Telescope together with a statistical method that could be applied to find Earth-like planets from among the 1235 candidates released in February. “I’m here to present a new technique exemplified by the discovery of Kepler 10C” said Francois Fressin of Harvard-Smithsonian Center for Astrophysics to a packed press conference room.
Fressin tells Nature that although the statistical method he described has been used before – to confirm Kepler 9d — this is the first time the team was able to use it with a Kepler-derived probability for the likely frequency of small rocky planets, and show that probability was far greater than that of the alternatives; combinations of eclipsing stars that might mimick the signal.
Like its rocky sibling, Kepler 10B, 10C is expected to be a scorched, molten Earth orbiting too close to its host star for liquid water to exist. But the technique used to find it may also work for other planets that exist in the habitable zone where liquid water can exist.
Planetary discoveries are coming thick and fast from the 0.95 meter space telescope, with the team deluged by a flood of data that they still need to interpret. And it seems other astronomers keen to get their hands on that will have to wait. Bill Borucki, Kepler’s principal investigator, told the press conference his team did not expect to make its next data release until June 2012. He said a pipeline set up to process candidates for smaller planets has only come online in the last few weeks and the team wants time to work on it before releasing the data, to avoid premature claims that later have to be retracted.
Image: Kepler’s field of view / NASA
Corrected May 27: the primary difference between the Kepler 10c analysis and that used for Kepler 9d was misstated in an earlier version and this has been corrected