Posted on Thursday, December 17 2009 @ 14:30 CET by Thomas De Maesschalck
Scientists have discovered a new planet with a mass 6.55 times that of the Earth. The planet is likely to harbor liquid water, but is estimated to have surface temperatures of at least 120°C. More info can be read
at ARS Technica.
There are a number of ways this could come about, but the two most likely ones are a rocky core surrounded by hydrogen gas, or planet with roughly equal amounts of rocky material and water. The scientists involved lean heavily towards the latter explanation, since it's highly unlikely that there would be much free hydrogen floating around the inner part of a planetary disk that's rich enough in iron and rocky material to produce a solid core. So, the conclusion is that GJ 1214b probably has a thin shell of hydrogen and helium for an atmosphere, and then a massive ocean above a silicate and iron core.
Depending on how reflective the planet's atmosphere is, it may have temperatures as high as 555K, or as low as 393K—the latter figure is only 20°C above the boiling point of water. That's far and away the coolest planet we've yet spotted, and a far cry from the only other super earth we know much about, which is hot enough that its atmosphere probably contains vaporized titanium oxides. Given the gravitational differences with Earth, which will cause pressure to build up rapidly, and it's apparent that at least some of the water will almost certainly be liquid.
