Water-World Found! Astronomers from the Harvard-Smithsonian Center for Astrophysics (CfA) say they've spotted a super-Earth waterworld orbiting a red type M star some 40 lightyears from Earth. The body - dubbed GJ1214b - is circling dim host star GJ1214 every 38 hours at a distance of just 1.3 million miles. The star's modest surface temperature of 2,700°C, though, means that GJ1214b itself is a balmy 200°C. The planet has a mass and radius of 6.5 and 2.7 times that of Earth, respectively. The density obtained from these figures "suggests that GJ1214b is composed of about three-fourths water and other ices, and one-fourth rock". CfA graduate student Zachory Berta, who first identified the planet, said: "Despite its hot temperature, this appears to be a waterworld. It is much smaller, cooler, and more Earthlike than any other known exoplanet." The discovery was made as part of the ground-based MEarth Project, which uses "an array of eight identical 16-inch-diameter RC Optical Systems telescopes that monitor a pre-selected list of 2,000 red dwarf stars".
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