WASP-189b is located 322 light years distant from our planet. It is an ultra-hot gas giant world, similar to Jupiter, where temperatures reach 3200 ° C , but which has a layered atmosphere surprisingly similar to that of Earth, according to a study carried out by scientists from Sweden and Switzerland and published in the journal Nature Astronomy.
Using high-resolution spectroscopy, researchers discovered this planet orbiting its bright host star HD 133112 by the Wide Angle Search for Planets (WASP) project in 2018. Now, they have identified that it contains an “exotic cocktail” of titanium oxide, iron, titanium, chromium, vanadium, magnesium and manganese.
WASP-189b is 20 times closer to its star than Earth is to the Sun and, due to its proximity, a year only lasts 2.7 days in a scenario with temperatures so high that they would be able to vaporize iron. However, thanks to this alignment with its star, researchers can study its atmosphere in detail.
Unequivocal detection of titanium oxide
“We measure the light coming from the planet’s host star and passing through the planet’s atmosphere. The gases in its atmosphere absorb part of the light from the stars, in a similar way to ozone that absorbs part of the sunlight in the Earth’s atmosphere and therefore leave their characteristic ‘fingerprint’ ”, explained Bibiana Prinoth from Lund University and leader of the work. “With the help of [ESO’s planet hunter] HARPS, we were able to identify the corresponding substances.”
What this new research reveals is that WASP-189b’s atmosphere may have different layers, just like Earth’s. While Earth’s atmosphere contains layers, such as Earth’s troposphere, the lowest layer extending from sea level beyond the highest mountain peaks, which contains most of the water vapor or like the stratosphere, whose ozone layer protects us from the Sun’s harmful ultraviolet radiation. This planet appears to have a layer of titanium that may act in a similar way.
As well as finding traces of iron, chromium, vanadium, magnesium and manganese in its atmosphere, the team also detected titanium oxide. Although titanium oxide is very rare on Earth, it could play an important role in the atmosphere of this gas giant, similar to that of ozone in the Earth’s atmosphere.
“Titanium oxide absorbs short-wave radiation, such as ultraviolet radiation. Therefore, its detection could indicate a layer in WASP-189b’s atmosphere that interacts with stellar radiation in a similar way as the ozone layer does on Earth,” said Kevin Heng, professor of astrophysics at the University of Bern, NCCR PlanetS member and co-author of the study.
This research represents a new milestone in probing exoplanet atmospheres, which is where we are most likely to detect signs of extraterrestrial life, and WASP-189b is perhaps the most extreme of the approximately 4,300 exoplanets that have been confirmed to date, so It appears as a very exotic planet.
Referencia: “Titanium oxide and chemical inhomogeneity in the atmosphere of the exoplanet WASP-189 b” by Bibiana Prinoth, H. Jens Hoeijmakers, Daniel Kitzmann, Elin Sandvik, Julia V. Seidel, Monika Lendl, Nicholas W. Borsato, Brian Thorsbro, David R. Anderson, David Barrado, Kateryna Kravchenko, Romain Allart, Vincent Bourrier, Heather M. Cegla, David Ehrenreich, Chloe Fisher, Christophe Lovis, Andrea Guzmán-Mesa, Simon Grimm, Matthew Hooton, Brett M. Morris, Maria Oreshenko, Lorenzo Pino and Kevin Heng, 27 January 2022, Nature Astronomy.
DOI: 10.1038/s41550-021-01581-z
