A sweltering exoplanet WASP-189b, located about 322 light years away from Earth, may harbour a complex layered atmosphere somewhat like that on our world, a new study suggests.
The research was conducted by an international team that included researchers from the University of Bern and University of Genevaand led by the University of Lund, and involved the use of the HARPS spectrograph at the La Silla Observatory in Chileto.
“We measured the light coming from the planet’s host star and passing through the planet’s atmosphere. The gases in its atmosphere absorb some of the starlight, similar to ozone absorbing some of the sunlight in Earth’s atmosphere, and thereby leave their characteristic ‘fingerprint.' With the help of HARPS, we were able to identify the corresponding substances,” said Bibiana Prinoth, doctoral student at Lund University and lead author of the study.
According to a news release posted on the University of Bern's website, the team detected the presence of a gas called titanium oxide, which could play a role similar to that of ozone in our planet's atmosphere.
“Titanium oxide absorbs short wave radiation, such as ultraviolet radiation. 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," said study co-author Kevin Heng, a professor of astrophysics at the University of Bern.
Prinoth also noted that, as “fingerprints” of the various gases in the planet's atmosphere were “slightly altered” as compared to the team's expectations, and in different ways," the researchers believe “this indicates that they exist in different layers – similarly to how the fingerprints of water vapour and ozone on Earth would appear differently altered from a distance, because they mostly occur in different atmospheric layers.”
“In the past, astronomers often assumed that the atmospheres of exoplanets exist as a uniform layer and try to understand it as such,” said another co-author of the study Jens Hoeijmakers, associate senior lecturer at Lund University. “But our results demonstrate that even the atmospheres of intensely irradiated giant gas planets have complex three-dimensional structures.”