For the first time, astronomers were able to analyze the atmosphere of an exoplanet in the class known as super Earths. Using data gathered from the Hubble Space Telescope and using new analysis techniques, the planet 55 Cancri e was revealed to have a dry atmosphere without any indications of water vapor. These results suggest that the planet’s atmosphere consists mainly of hydrogen and helium.
Super-earth is a special class of exoplanets that are rocky and similar to ours only larger. They go from roughly one to two times the mass of Earth up to about 10 Earth masses. Super Earths are substantially below the mass of the solar system’s ice giants Uranus and Neptune which are 15 and 17 Earth’ masses respectively.
The term super Earth refers only to the mass of the planet, it says nothing about the surface conditions or its habitability. So, the exoplanet studied by Hubble — 55 Cancri e — is a super Earth with a mass of eight Earth masses. It is located in the planetary system of 55 Cancri, a star about 40 light-years from Earth.
Using observations made with the Wide Field Camera 3 or also known as WFC3 on board of Hubble, scientists were able to analyze the atmosphere of this exoplanet. This is important because this is the first detection of gases in the atmosphere of a super Earth — it hasn’t been done before on a planet of this size.
Although, the WFC3 instruments on Hubble has been used to probe the atmospheres of two others super-Earths in the pass, no spectral features were found in the previous observations. 55 Cancri e is an unusual super because it orbits very close to its parent star — a year on this exoplanet last for only 18 hours. And temperatures on the surface is thought to reach around 2,000°C.
It turns out that being so close to its parent star was a good thing because this allowed the team to use a new analysis technique to extract information about the planet while it was transiting in front of its host star. So what they did was… they made observations by scanning the wfc3 very quickly across the star to create a number of spectra. Then they combine those spectrums process into software and from that the researchers were able to retrieve the spectrum of 55 Cancri e that was embedded in the light of the parent star.
This technique allows the team to examine the atmosphere in detail and revealed the presence of hydrogen and helium, like I said, but no water vapor.
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.
The observations of 55 Cancri e’ 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.
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 and how it might have formed and evolved, and this has important implications for 55 Cancri e and other super-Earths,
said Giovanna Tinetti, also from UCL, UK.
Now, we have one of the first insights into the atmosphere of a super-Earth, we have clues as to what the planet is currently like and how might have formed and evolved and this has important implications for 55 Cancri e and other super-Earths.
Interestingly, another thing they found were hints of hydrogen cyanide which is a marker for a carbon rich atmosphere. One of the team astronomers say that such an amount of hydrogen cyanide would indicate an atmosphere with a very high ratio of carbon dioxide and they also say if the presence of hydrogen cyanide in other molecules is confirmed in a few years by the next generation of infrared telescopes, it would support the theory that this planet is indeed carbon rich and a very exotic place.
Such an amount of hydrogen cyanide would indicate an atmosphere with a very high ratio of carbon to oxygen,
said Olivia Venot, KU Leuven, who developed an atmospheric chemical model of 55 Cancri.
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,
concludes Jonathan Tennyson, UCL.
Although hydrogen cyanide, or prussic acid, is highly poisonous, so it is perhaps not a planet I would like to live on!
One more thing, hydrogen cyanide also called prussic acid, is highly poisonous, So… this place may not be high on our list of tourist attractions.
This planet is highly poisonous, so it is perhaps not a place I would like to live on,
Note: 55 Cancri e has previously been dubbed the “diamond planet” because models based on its mass and radius have led to the idea that its interior is carbon-rich.