Scientists have been looking for a planet that could support life for decades, and in their research they have discovered various different looking and interesting planets. However, WASP-18b, also known as the Death Planet, is an exoplanet they found to be very unusual. The planet looks like a normal uninhabitable planet, although what amazed scientists is that its peculiar upper atmosphere almost entirely consists of carbon monoxide.
Because WASP-18b’s stratosphere consists of mostly carbon monoxide, and the planet doesn’t have any water at all, scientists that discovered the planet think that it resembles other hot Jupiters but that it perhaps formed in a different way, the Independent reports.
“The composition of WASP-18b defies all expectations,” said Kyle Sheppard of NASA’s Goddard Space Flight Center, lead author of the study published in the Astrophysical Journal letters, in a statement. “We don’t know of any other extrasolar planet where carbon monoxide so completely dominates the upper atmosphere.”
The news of the discovery of WASP-18b encouraged some to give it the nickname the Death Planet. However, it is important to know that this exoplanet is not any more brutal than any of its hot Jupiter siblings, especially since we already have such planets in our Solar System, Jupiter and Saturn, which effortlessly made the spacecraft Cassini plunge into its atmosphere.
What makes the Death Planet brutal is that its stratospheric composition is mostly carbon monoxide. But, the other hot Jupiters located in different solar systems have atmospheres consisting of titanium oxide and vanadium oxide. More importantly, the team behind the research found signs that chemicals absorb the sunlight in WASP-18b’s atmosphere, which is the same as what the chemicals do found on other hot Jupiters. However, when they analyzed the light they spotted from the planet, they concluded that it doesn’t look like any other planet they’ve researched before.
According to the models they ran, the atmosphere of the exoplanet needed to have just carbon dioxide and carbon monoxide, and nothing else. The scientists compared their findings with Venus which consists of carbon dioxide, and found that there should be enough oxygen in the atmosphere to form water on WASP-18b, which they couldn’t find. Also, they have never seen sun-absorbing upper atmosphere which was built only out of carbon monoxide.
“This rare combination of factors opens a new window into our understanding of physicochemical processes in exoplanetary atmospheres,” co-author of the paper, Nikku Madhusudhan, an astronomer at the University of Cambridge in the United Kingdom, said in a press release.