Hubble Successfully Detected Super-Earth Atmosphere for the First Time

February 19, 2016 | Joanne Kennell

artist's impression shows the super-Earth 55 Cancri e in front of its parent star
Photo credit: M. Kornmesser/ESA/Hubble

It is nicknamed the “diamond planet” because its interior is believed to be carbon-rich.

Super-Earth exoplanet 55 Cancri e, nicknamed the “diamond planet,” had its atmosphere successfully detected — marking the first time an exoplanet’s atmosphere has ever been measured.  It turns out its atmosphere is composed mainly of hydrogen and helium.  It was previously dubbed the “diamond planet” because models predicted that its interior is carbon-rich based on its mass and radius .

Super-Earths have a greater mass than Earth, but they are still much smaller than gas giants and are considered the most common planet type in our galaxy.

55 Cancri e, also known as “Janssen,” has a year that lasts 18 hours and temperatures on its surface reach around 3630 degrees Fahrenheit (2000 degrees Celsius).  The planet is located in a solar system that orbits 55 Cancri, also known as “Copernicus,” which is a star in the Cancer constellation roughly 40 light-years from Earth.  Since 55 Cancri is an extremely bright star, the team was able to get information about 55 Cancri e.

Using new analysis techniques on data from the NASA/ESA Hubble Space Telescope and the Wide Field Camera 3 (WFC3), a team of researchers led by University College London (UCL) examined the atmosphere of 55 Cancri e.

SEE ALSO: “Impossible” Compounds Found on Super, Earth-like Planets

“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 a press 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,” Tsiaras continued.

WFC3 works by very quickly scanning across the star to create a number of spectra, allowing the researchers to retrieve spectral fingerprints of 55 Cancri e.  It was also used to probe the atmosphere of two other super-Earths, but no spectral features were found in those studies.

“This result gives a first insight into the atmosphere of a super-Earth. 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,” said Professor Giovanna Tinetti, also from UCL.

Interestingly, their results also showed a signature for hydrogen cyanide — a marker for a carbon-rich atmosphere.  “Such an amount of hydrogen cyanide would indicate an atmosphere with a very high ratio of carbon to oxygen,” said Dr Olivia Venot, KU Leuven, Belgium.

“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 Professor Jonathan Tennyson of UCL.  “Although, hydrogen cyanide or prussic acid is highly poisonous, so it is perhaps not a planet I would like to live on!”

Me neither!

Hopefully the researchers can use these techniques to learn about the atmospheres of the many other Super-Earths hanging out in our galaxy.

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