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Categorizing extrasolar planets

More than three-quarters of planets outside our solar system discovered by the Kepler space telescope fall into two new planetary classes: the super-Earth and the mini-Neptune. .

A preponderance of little Neptunes
Geoffrey Marcy, University of California at Berkeley; NASA. | Patterson Clark / The Washington Post. Published on January 6, 2014, 4:37 p.m.
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