A NASA team has found an indication that the oversized exoplanet WASP-18b is protected in a smothering stratosphere filled with carbon monoxide and devoid of water. Conclusions from NASA’s Hubble and Spitzer telescopes have enabled a team of investigators to find a sign that the exoplanet WASP-18b has a stratosphere filled with carbon monoxide and without any water. The planet relates to a class of bodies identified as “Hot Jupiters”, and the scientists have observed that the planet which is strangely close to its host star may have developed as a different planetary development process as compared to gas giants in other planetary systems, as well as our solar system.
The planet, which is approximately 325 light years distant from Earth was being examined as part of a study to understand exoplanets with stratospheres. Typically, the stratosphere of a planet includes molecules that incorporate the radiation from the host star and delivers the stored energy as heat. The spectral fingerprint of the star, which enables scientists to recognize its composition by looking particularly at the light released by the atmosphere of the planet, was unlike anything is seen before.
Kyle Sheppard of NASA’s Goddard Space Flight Center says that the composition of WASP-18b challenges all expectations. We do not know of any other extrasolar planet where carbon monoxide so absolutely controls the upper atmosphere.
The conclusions show that WASP-18b has hot carbon monoxide in the stratosphere and chill carbon monoxide in the layer of the atmosphere here, called the troposphere. The team discovered this by identifying two types of carbon monoxide signatures, an inhalation signature at a wavelength of about 1.6 micrometres and an ejection signature at approximately 4.5 micrometres. This is the first time researchers have discovered both types of fingerprints for a single type of molecule in an exoplanet’s environment. In this theory, another probable fit for the measurements is carbon dioxide, which has a comparable fingerprint. The researchers conducted this out because if there were enough oxygen available to form carbon dioxide, the climate also should have some water vapour.
The investigators had to utilize computer simulations to reach the resolution that the planet was cloaked by a thick layer of carbon monoxide. Carbon monoxide has an alike spectral fingerprint to carbon dioxide, but the occupancy of the last molecule was ruled out considering that the spectral lines did not symbolize the presence of water at all, and the stratosphere was supposed to have more water if there was sufficient oxygen to form carbon dioxide.
The researchers pointed out that the launch of the James Webb Space Telescopes and other follow up missions would provide a deeper understanding of the variety of exoplanets.