Scientists detect gases in super-Earth atmosphere for first time

"This is a very exciting result," said researcher Angelos Tsiaras.
By Brooks Hays   |   Feb. 16, 2016 at 1:16 PM

LONDON, Feb. 16 (UPI) -- For the first time, scientists have completed a detailed analysis of the atmosphere of a super-Earth, exoplanet 55 Cancri e.

The alien world is eight times the mass of Earth; it circles 55 Cancri, a star in the Cancer constellation 40 light-years from our solar system.

Astronomers used data from the Hubble Space Telescope and a novel processing technique to detect the gases surrounding the exoplanet. Their findings are detailed 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," Angelos Tsiaras, a PhD student at University College London, said in a news release. "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."

Researchers believe super-Earths like 55 Cancri e are the most common type of exoplanet in the universe. This particular super-Earth is quite close to its host star, with an orbit lasting just over 18 hours. Its surface temperature is believed to be upwards of 2000 degrees Celsius.

Astronomers detected the exoplanet's atmosphere by quickly scanning Hubble's Wide Field Camera 3 across the face of its host star. The scan picked up the exoplanet cast in the light of the star, and newly designed computer algorithms pulled out the spectral signatures of gases surrounding 55 Cancri e.

"This result gives a first insight into the atmosphere of a super-Earth," said Giovanna Tinetti, a professor of astronomy and physics at UCL. "We now have clues as to what the planet is currently like, how it might have formed and evolved, and this has important implications for 55 Cancri e and other super-Earths."

Previous studies of the super-Earth's mass and radius suggest its insides are carbon-rich, leading scientists to dub 55 Cancri e the "diamond planet."

Spectral signatures collected in the latest study hint at the presence of hydrogen cyanide -- lending credence to the nickname. Hydrogen cyanide is typically found in atmospheres with a high carbon-to-oxygen ratio.

"If the presence of hydrogen cyanide and other molecules is confirmed in a few years' time by the next generation of infrared telescopes, it would support the theory that this planet is indeed carbon rich and a very exotic place," explained Jonathan Tennyson, also a UCL astronomy professor.


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