New Type of Planet Discovered: Waterworld

Posted on February 21, 2012

GJ1214b Waterworld

A new type of planet has been discovered with NASA's Hubble Space Telescope. The extrasolar planet GJ1214b is described as a waterworld enshrouded by a thick, steamy atmosphere.

Astronomer Zachory Berta (Harvard-Smithsonian Center for Astrophysics) and colleagues have proved the planet is made up mostly of water. They used Hubble's WFC3 instrument to study GJ1214b when it crossed in front of its host star.

Berta says, "GJ1214b is like no planet we know of. A huge fraction of its mass is made up of water."

When a planet crosses in front of its host star (as pictured above) the star's light is filtered through the planet's atmosphere, giving clues to the mix of gases. The researchers found the spectrum of GJ1214b to be featureless over a wide range of wavelengths, or colors. The atmospheric model most consistent with the Hubble data is a dense atmosphere of water vapor. The researchers say GJ1214b has much more water than Earth, and much less rock.

Berta says, "The high temperatures and high pressures would form exotic materials like 'hot ice' or 'superfluid water' - substances that are completely alien to our everyday experience."

A research paper about GJ1214b was published here in The Astrophysical Journal.

Image: NASA, ESA, and D. Aguilar (Harvard-Smithsonian Center for Astrophysics)