Kepler just won't quit! Just after discovering a slightly-larger-than-Earth planet in the Habitable Zone, Kepler now announces a pair of actually-Earth-sized planets. These planets are in very, very short period orbits (6 and 20 days), and so sit very, very close to their parent star (Mercury orbits the Sun every 88 days). They're super hot!This bodes very well for Kepler's ultimate goal -- combining the features of the Kepler-20 and Kepler-22 systems: Earth sized planets in the Habitable Zone, maybe even with giant planets further out (or closer in?). It will take a while - these planets were discovered despite their very small size because they orbit so frequently that Kepler could see them transit their parent star many, many times, and so the signal built up over time. A planet in the Habitable Zone will only transit 3-7 times over the course of the mission, and so the analysis is much, much harder, especially for such small planets.
Unfortunately, we're in the middle of a big upgrade to exoplanets.org and our undergraduate maintainers Katherina and Eunkyu are away for the holidays, so Kepler-20 may have to wait a little while before it appears in the Exoplanet Orbit Database. Soon though!
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