Published On: Thu, Feb 18th, 2016

First Detection of Super-Earth Atmosphere

For the first time astronomers were able to analyse the atmosphere of an exoplanet in the class known as super-Earths. Using data gathered with the NASA/ESA Hubble Space Telescope and new analysis techniques, the exoplanet 55 Cancri e is revealed to have a dry atmosphere without any indications of water vapour. The results indicate that the atmosphere consists mainly of hydrogen and helium.

Artist’s impression of 55 Cancri e

The international team, led by scientists from University College London (UCL) in the UK, took observations of the nearby exoplanet 55 Cancri e, a super-Earth with a mass of eight Earth-masses. It is located about 40 light-years from Earth.

Using observations made with the Wide Field Camera 3 (WFC3) on board the NASA/ESA Hubble Space Telescope, the scientists were able to analyse the atmosphere of this exoplanet. This makes it the first detection of gases in the atmosphere of a super-Earth. The results allowed the team to examine the atmosphere of 55 Cancri e in detail and revealed the presence of hydrogen and helium, but no water vapour. These results were only made possible by exploiting a newly-developed processing technique.

 

 

This is a very exciting result because it’s the first time that we have been able to find the spectral fingerprints that show the gases present in the atmosphere of a super-Earth, ” explains Angelos Tsiaras, a PhD student at UCL, who developed the analysis technique along with his colleagues Ingo Waldmann and Marco Rocchetto. “The observations of 55 Cancri e’s atmosphere suggest that the planet has managed to cling on to a significant amount of hydrogen and helium from the nebula from which it originally formed.

Super-Earths like 55 Cancri e are thought to be the most common type of planet in our galaxy. They acquired the name ‘super-Earth’ because they have a mass larger than that of the Earth but are still much smaller than the gas giants in the Solar System. The WFC3 instrument on Hubble has already been used to probe the atmospheres of two other super-Earths, but no spectral features were found in those previous studies.

Unfortunately, 55 Cancri e probably doesn’t support life. Its atmosphere appears to be comprised almost entirely of hydrogen and helium with no traces of water. Plus, the planet is so close to its star that a year there lasts 18 Earth-hours and the surface of the planet can get as hot as 2, 000 degrees C.

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