And one of those layers is even strongly reminiscent of our own ozone layer, which is very important for life.

About 322 light-years away we find planet WASP-189b. And WASP-189b is not just one of them. For example, the so-called ‘ultra-hot Jupiter’ is included in the list of most extreme exoplanets. Researchers wanted to a new study sometimes the fine knowledge of its atmosphere. And that leads to some interesting discoveries.

More about WASP-189b
Exoplanet WASP-189b is said to be about 322 light-years away from Earth and orbits the hot star HD 133112. The planet was extensively studied in 2020 using the CHEOPS space telescope. And thanks to those previous observations, we know that WASP-189b is one of the hottest and most extreme planets known to us. Among other things, WASP-189b is much larger than thought at nearly 1.6 times the radius of Jupiter from our own solar system. Moreover, the planet is a real ‘ultra-hot Jupiter’. Hot Jupiters, as the name suggests, are giant gas planets that look a bit like Jupiter. However, they orbit much closer to their host star and are thus heated to extreme temperatures. The researchers think that WASP-189b is about 20 times closer to its star than Earth is to the sun. The planet completes one orbit around its parent star in just 2.7 days. This means that temperatures can reach a blistering 3200 degrees Celsius.

As you probably know, the Earth’s atmosphere is not a uniform shell, but consists of several layers, each of which has characteristic properties. For example, on the lowest floor we find the troposphere. This contains the most water vapor and is the layer in which the weather phenomena take place. The layer above it, the stratosphere, contains the famous ozone layer that protects us from the sun’s harmful ultraviolet rays.

Atmosphere of WASP-189b

However, the question is how exactly the atmospheres of exoplanets are constructed. Especially those of the extreme planets, such as WASP-189b. However, using the HARPS spectrograph at the La Silla Observatory in Chile, the researchers were now able to get a closer look at the atmosphere of this Jupiter-like planet for the first time. And that leads to an interesting discovery. For example, WASP-189b appears to have a complex and exotic atmosphere, which – just like the Earth – consists of different layers.


In the study, the researchers measured the light coming from the parent star of WASP-189b and seeping through its atmosphere. “The gases in the atmosphere absorb some of the starlight – similar to ozone that absorbs some of the sunlight in Earth’s atmosphere – leaving behind a characteristic ‘fingerprint’,” explains researcher Bibiana Prinoth. “Using HARPS we were able to identify the corresponding substances.” The researchers discovered that the atmosphere of WASP-189b contains, among other things, iron, chromium, vanadium, magnesium and manganese.

Ozone layer

In addition, the team found titanium oxide in the atmosphere of WASP-189b. And that’s particularly interesting. The researchers suspect that this compound in the atmosphere of the exoplanet plays a similar role to ozone in the Earth’s atmosphere. “Titanium oxide also absorbs ultraviolet radiation,” explains researcher Kevin Heng. “Its detection could therefore indicate a layer in the atmosphere of WASP-189b that interacts with stellar radiation in the same way that the ozone layer on Earth does.”


In the analysis, the researchers found that the observed ‘fingerprints’ of the different gases had changed slightly compared to their expectation. “We believe that strong winds and other processes can cause those changes,” said Prinoth. And that could mean that the atmosphere of the WASP-189b is made up of different layers, according to the researchers.

This discovery will change the way astronomers study exoplanets, according to Prinoth. In the past, astronomers often assumed that the atmospheres of exoplanets consisted of a uniform layer. But that doesn’t seem quite the case. “The new results show that even the atmospheres of intensely irradiated, gigantic gas planets have complex and three-dimensional structures,” concludes researcher Jens Hoeijmakers.