Earth's Larger, Gassy Twin Discovered 200 Light-Years Away

Scientists using data from NASA's Kepler spacecraft have located a planet that weighs the same as Earth. The only catch? It's one hot and gassy planet.

Planet KOI-314c orbits a red dwarf star 200 light-years away and has an estimated temperature of 220 degrees Fahrenheit. KOI-314c weighs the same as Earth, only it's 60 percent larger, leading the researchers involved in the study to speculate that the planet contains a very thick and gaseous atmosphere.

"This planet might have the same mass as Earth, but it is certainly not Earth-like," says David Kipping of the Harvard-Smithsonian Center for Astrophysics (CfA), lead author of the discovery. "It proves that there is no clear dividing line between rocky worlds like Earth and fluffier planets like water worlds or gas giants."

Planet KOI-314c wasn't easy to find, and was actually an accidental discovery when scientists were looking for exomoons using Kepler data. Calculating the mass of KOI-314c wasn't easier either, and the team of scientists involved in the study had to use a more unconventional method known as transit timing variations. This technique relies on the wobbling between two planets, rather than the wobbling between a star and its planet.

"Rather than looking for a wobbling star, we essentially look for a wobbling planet," explains second author on the study David Nesvorny. "Kepler saw two planets transiting in front of the same star over and over again. By measuring the times at which these transits occurred very carefully, we were able to discover that the two planets are locked in an intricate dance of tiny wobbles giving away their masses."

A paper detailing the findings has been submitted for publication in The Astrophysical Journal.