Abundant `mini-Neptunes` form new class of alien planets

Zee Media Bureau

Kepler`s cornucopia of alien worlds has found a new entrant in the form of a new kind of planet. NASA`s Kepler spacecraft has found the ground-based follow-up observations of planets which reveal the masses and densities of 16 new planets ranging between one and four times the size of Earth. Many of these have a rocky core surrounded by a puffed-up envelope of gas, which scientists are calling "sub-Neptunes" or "mini-Neptunes." Five of the new planets are rocky, including Kepler-406b, a planet 1.4 times the radius of Earth that orbits its planet every 2.4 days. "This marvelous avalanche of information about the sub-Neptunian planets is telling us about their core-envelope structure, not unlike a peach with its pit and fruit," study leader Geoff Marcy, a professor of astronomy at University of California, Berkeley, said in a statement. Geoff Marcy and colleagues confirmed 41 of the planets discovered by Kepler, which spies the tiny dimming in starlight when a planet transits in front of its host star. Using this Doppler method, the team found the mass of 16 of the planets. Combining the planetary masses and their radii, inferred from the Kepler dimming data, the team determined the planets` densities, offering clues to whether they are rocky, gaseous or some hybrid of the two.