Astronomers have discovered a new type of ocean-covered alien planet that is the only one of its kind ever found inside or outside our solar system.
Researchers at the Harvard-Smithsonian Center for Astrophysics in the northeastern state of Massachusetts describe the planet, called GJ-1214b, as a waterworld surrounded by a thick, steamy atmosphere. They say the exoplanet is nearly three times the diameter of the Earth, and weighs nearly seven times as much.
The waterworld’s size and mass, confirmed by data from the Hubble space telescope, qualify it as a so-called super-Earth, a category that includes exoplanets less than 10 times the mass of the Earth. However, astronomers had to create a new planet classification to accommodate the new watery super-Earth, which did not fit any of the previously-known types, such as rocky, ice or gas. They say what makes the steamy exoplanet unusual is that a significant portion of its mass is composed of water, and it has much less rock than the Earth – or any other known rocky planet.
The exoplanet is a mere 40 light years away, close, by cosmic standards. It orbits a red dwarf star every 38 hours from a distance of only 2 million kilometers.
Astronomers say that proximity to its sun sends surface temperatures on the planet soaring to around 230 degrees Celsius, making it too hot to host life as we know it.
The ocean-covered world was first detected in 2009 with ground-based observations, but it was new infrared data obtained from the Hubble space telescope that gave scientists additional details about the exoplanet’s steamy atmosphere and watery surface.
A report on the watery exoplanet is published online in Astrophysical Journal.