First detection of gases in super-Earth atmosphere

The first successful detection of gases in the atmosphere of a super-Earth reveals the presence of hydrogen and helium, but no water vapour, according to UCL researchers. The exotic exoplanet, 55 Cancri e, is over eight times the mass of Earth and has previously been dubbed the 'diamond planet' because models based on its mass and radius have led some astronomers to speculate that its interior is carbon-rich. Using new processing techniques on data from the NASA/ESA Hubble Space Telescope, a UCL-led team of European researchers has been able to examine the atmosphere of 55 Cancri e in unprecedented detail. The results will be published in the Astrophysical Journal . "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," said Angelos Tsiaras, a PhD student at UCL who developed the analysis technique along with colleagues Dr Ingo Waldmann and Marco Rocchetto in UCL Physics & Astronomy.  "Our analysis of 55 Cancri e's atmosphere suggests that the planet has managed to cling on to a significant amount of hydrogen and helium from the nebula from which it formed." Super-Earths are thought to be the most common planetary type in our galaxy and are so-called because they have a mass larger than Earth but are still much smaller than the gas giants in the Solar System. The Wide Field Camera 3 (WFC3) on Hubble has already been used to probe the atmosphere of two super-Earths, but no spectral features were found in these previous studies.