Super Earth GJ 1214 b

Is there a water planet just 42 light years from Earth? Japanese scientists this week said their investigations of a nearby exoplanet suggest it "is likely to have a water-rich atmosphere."

Gliese 1214 b (GJ 1214 b), discovered in 2009, is a so-called super-Earth—an extrasolar planet that's larger and more massive than our own but significantly smaller than icy giants like Uranus or Neptune. Not much is known about super-Earths, how they form, or why our own solar system doesn't have one despite their apparent prevalence in other star systems.

But now it appears that we may have a better idea of the atmospheric conditions on at least one of them. GJ 1214-b is located in the constellation Ophiuchus and is about 2.5 times the size of Earth and about seven times more massive.

While GJ 1214-b isn't listed as a prime candidate for life among known exoplanets orbiting within their stars' habitable zones, it was suspected of having liquid water from the time of its discovery.


Using a pair of optical cameras in the Subaru Telescope, the Japanese research team observed the planetary transits of GJ 1214 b in an investigation into the super-Earth's atmospheric composition, the scientists said. The team said a lack of strong Rayleigh scattering in their observations made it unlikely the planet possesses a "cloudless hydrogen-dominated atmosphere," and instead "implies that the planet has a water-rich or a hydrogen-dominated atmosphere with extensive clouds."

The research team said previous data collected from observing GJ 1214 b in different colors suggested that it's more likely the planet has a cloudy, water-rich atmosphere rather than one dominated by hydrogen clouds.

Though the researchers said GJ 1214-b's "very faint host star in blue light poses a challenge for researchers seeking to determine whether or not the planet's atmosphere has strong Rayleigh scattering," they were able to achieve extremely sensitive results using the Subaru Telescope's powerful light-collecting 8.2 m mirror.