Astronomers have just taken a look into the atmosphere of one of the most extreme exoplanets yet observed. Although it is not habitable, WASP-189b is the first exoplanet where scientists have been able to investigate different atmosphere layers, each with its unique chemical compositions and properties.
WASP-189b, located approximately 322 light-years away, is approximately 1.6 times the size of Jupiter and orbits its star at a rapid 2.7-day period. Because the star is young and hot, the surface temperatures of WASP-189b on its dayside can reach 3,200 degrees Celsius (5,792 degrees Fahrenheit), making the planet hotter than some stars.
It's also one of the most visible transiting exoplanets, meaning it passes between us and its star. As a result, it's particularly appealing for atmospheric research.
The researchers discovered traces of titanium oxide, which they claim has never been conclusively confirmed in an exoplanetary atmosphere previously. Titanium oxide is rare in nature on Earth, but its presence on WASP-189b may be helping to shape the atmosphere.
"Titanium oxide absorbs short-wave radiation, such as ultraviolet radiation," astrophysicist Kevin Heng of the University of Bern, said in a statement.
"Its detection could therefore indicate a layer in the atmosphere of WASP-189b that interacts with the stellar irradiation similarly to how the ozone layer does on Earth."
Another huge hint was that the team was also observing layers in the exoplanet's atmosphere. Elements in space are identified spectrally, which means that we divide the light detected by our detectors into the entire spectrum and seek stronger or darker lines. These show that anything is either amplifying or absorbing those wavelengths, which are referred to as emission or absorption lines.
Absorption lines can then be traced back to specific elements known to absorb those wavelengths. The absorption lines from WASP-189b, however, were not precisely where the researchers expected them to be.
Strong winds and other factors, according to scientists, could cause these changes. They believe that the fingerprints of different gases were altered in different ways because they exist in distinct levels, comparable to how the fingerprints of water vapor and ozone on Earth would appear differently altered from a distance because they predominantly reside in separate atmospheric layers.
We're not going to WASP-189b anytime soon, obviously. Even if we were, life as we know it would be extinct before we even set foot on the planet; however, the research is still relevant to the search for life.
It marks a new milestone in the study of exoplanetary atmospheres, which are where we're most likely to find signs of extraterrestrial life.
The research has been published in Nature Astronomy.
