Forty light-years from Earth, the planetary system 55 Cancri hosts five planets, all discovered via radial velocity measurements. Among these planets is super-Earth 55 Cancri e. It’s a hostile place, with years lasting only 18 hours and surface temperatures around 2,000 C. An artist’s impression depicts the planet as an orb of magma, mottled with fiery red among the charred gray.  

And now astronomers, using data from the Hubble Space Telescope, have successfully analyzed the atmosphere of the planet, making 55 Cancri e the first super-Earth to have its atmosphere analyzed.  

“The Wide Field Camera 3 (WFC3) onboard the Hubble Space Telescope, combined with the recently implemented spatial scanning technique, allows the spectroscopic observation of super-Earths, which is unprecedented,” wrote the researchers in their paper, which is slated for publication in the Astrophysical Journal.

The data revealed that the planet’s atmosphere is arid with no markers of water vapor. Instead, it’s dominated by a mixture of hydrogen and helium.

While no super-Earths exist inside the solar system, there are a plethora of them in the Milky Way galaxy. However, 55 Cancri e is unusual due to its close proximity to its parent star. The planet is about eight times the mass of Earth.

“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,” said Univ. College London’s Angelos Tsiaras, who is an author of the study.

The gleaned data also suggests the atmosphere is rich in hydrogen cyanide, which may indicate the atmosphere is carbon-rich.

“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,” said co-author Jonathan Tennyson. “Although hydrogen cyanide, or prussic acid, is highly poisonous, so it is perhaps not a planet I would like to live on.”