Hubble Studies 'Super-Earth' Atmosphere for First Time
Source: Discovery News
Hubble Studies 'Super-Earth' Atmosphere for First Time
FEB 16, 2016 12:05 PM ET // BY ELIZABETH HOWELL
For the first time, a super-Earth’s atmosphere has been analyzed — but don’t make any vacation plans to visit. The planet is blisteringly close to its planet star (exhibiting temperatures of 3,600 Fahrenheit or 2,000 Celsius) and has an atmosphere mostly made up of hydrogen and helium, like a gas giant planet.
Hydrogen and helium are common elements in young solar systems as those are the elements that make up young stars. Typically, however, smaller planets tend to lose the hydrogen and helium over time into space because their gravity is so low; the light elements escape, especially if a star’s radiation pushes against the atmosphere. Gas giant planets can hold on to those elements due to their stronger gravity.
On small planets, sometimes the hydrogen/helium atmosphere is replaced by a secondary atmosphere, which was the case on Earth. Our current mix of nitrogen, oxygen and carbon dioxide likely came from internal processes (such as volcanism) and the evolution of plants.
“We did not expect 55 Cancri e to retain this much of its primordial gas atmosphere,” said Ingo Waldmann, a post-doctoral research assistant at University College London who participated in the research, in an e-mail to Discovery News. Waldmann pointed out that the planet is the only known super-Earth with such a high temperature, but the astronomers had thought it would lose most of its atmosphere due to the intense radiation of its parent star. Why it held on to the hydrogen and helium is poorly understood.
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Read more: http://news.discovery.com/space/alien-life-exoplanets/hubble-studies-super-earth-atmosphere-for-first-time-160216.htm
