Scientists working with the Hubble Space Telescope have discovered a new type of planet they describe as a “water world” in a constellation 40 light years from Earth. The planet is smaller than Uranus, but larger than Earth.
The planet, called GJ 1214b, is about 2.7 times the diameter of the Earth and weighs close to 7 times as much, with the vast majority of its weight made up of water. The planet also is blanketed by a thick steamy atmosphere.
Measurements indicate the planet is much less dense than Earth, and thus contains more water and much less rock. That means the planet’s interior also is vastly different from Earth, said Zachory Berta, an astronomer with the Harvard-Smithsonian Center for Astrophysics and part of the team of scientists reporting on the discovery.
The planet orbits a red-dwarf star every 38 hours at a distance of 1.3 million miles, giving it an estimated temperature of 450 degrees Fahrenheit.
“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,” said Berta.
GJ 1214b is located in the constellation of Ophiuchus, also known as the Serpent Bearer. It formed far from its star, where water ice was plentiful, and migrated inward early in the system’s history, according to news releases announcing the discovery. In the process, it would have passed through the star’s habitable zone, where surface temperatures would be similar to Earth’s. How long it lingered there is unknown.
The scientific paper announcing the planet’s make-up is available on the web at http://www.spacetelescope.org/static/archives/releases/science_papers/heic1204.pdf