A nearby alien planet six times the size of the Earth is covered with a water-rich atmosphere that includes a strange "plasma form" of water, scientists say.
Astronomers have determined that the atmosphere of super-Earth Gliese 1214 b is likely water-rich. However, this exoplanet is no Earth twin. The high temperature and density of the planet give it an atmosphere that differs dramatically from Earth.
"As the temperature and pressure are so high, water is not in a usual form (vapor, liquid, or solid), but in an ionic or plasma form at the bottom the atmosphere — namely the interior — of Gliese 1214 b," principle investigator Norio Narita of the National Astronomical Observatory of Japan told SPACE.com by email. (The Strangest Alien Planets (Gallery))
Using two instruments on the Subaru Telescope in Mauna Kea, Hawaii, scientists studied the scattering of light from the planet. Combining their results with previous observations led the astronomers to conclude that the atmosphere contained significant amounts of water.
A wellspring of exotic water
Located 40 light-years from the solar system in the constellation Ophiuchus, the planet orbits its cooler, low-mass M-type star once every 38 hours, 70 times closer than Earth is to the sun.
Its close proximity means that its temperatures reach up to 540 degrees Fahrenheit (280 degrees Celsius). Six times as massive as Earth, Gliese 1214 b is less than three times as wide, falling between the Earth and the solar system's ice giants Uranus and Neptune in size.
The high temperatures of the planet may affect the hydrogen and carbon chemistry, which could produce a haze in the atmosphere. But determining if the weather is clear or perpetually overcast on Gliese 1214 b would be difficult, as differences in the two atmospheres are small.
"At high pressure and high temperature, the behavior of water is quite different from that on the Earth," Narita said. "At the bottom of the water-rich atmosphere of Gliese 1214 b, water should be a super-critical fluid."