Researchers explore an already known exoplanet and make an amazing discovery: It’s not just its water cycle that’s completely different from Earth’s.

Heidelberg – The infinite expansion of the universe ignites the imagination: what’s there to find? Over and over again, researchers make fascinating discoveries that often surprise themselves. The strangest celestial bodies have already been found, particularly in the region of exoplanets – which includes more than 300 so-called “hot Jupiters”. These are planets like Jupiter that orbit so close to their star that they are particularly hot. as well as the recent discovery that published in the journal Nature Astronomy became a hot Jupiter.

The exoplanet WASP-121b was actually discovered in 2015 at a distance of 855 light-years, but now researchers led by Thomas Mikal-Evans of the Max Planck Institute for Astronomy (MPIA) in Heidelberg have published new observations of the exoplanet – and their Have it in itself. For the first time, researchers have been able to observe the entire water cycle of an exoplanet. The NASA and ESA Hubble Space Telescopes were used for this purpose. The telescope observed two complete revolutions of the planet, because WASP-121b has a special property: it moves in a closed rotation around its star. This means that – as with our Moon – the same side of the planet always faces the star.

Space: Exoplanet WASP-121b has a very special water cycle

“Studying planets like WASP-121b, which are so different from the planets in our solar system, is exciting because they allow us to learn how to cope with extreme conditions,” says co-author Joanna Barstow, of the Open University in Milton Keynes. How does the atmosphere behave in Britain. And in fact, WASP-121b is an extreme planet: where the star is facing it is hot, while the side facing it is quite cold. According to the researchers, “Hubble” data shows that during the daytime the upper atmosphere reaches temperatures of up to 3000 °C – at these temperatures, water begins to glow and many molecules break down into their atomic components.

Exoplanet WASP-121b is a hot Jupiter – the planet of extremes

On the night side of the exoplanet, the temperature drops to about 1500 °C. This extreme temperature difference creates strong winds that move from west to east across the exoplanet, carrying broken water molecules with them. On the night side, it creates water vapor again, which breaks up again in the daytime – a cycle that repeats itself over and over again, as it never gets cold enough to cause water clouds or even rain.

Instead of clouds of water, the exoplanet WASP-121b consists mainly of clouds of metals such as iron, magnesium, chromium and vanadium. On the day side, these metals were found in gaseous form; on the night side, according to “Hubble” data, temperatures drop so much that the metals can condense into clouds. These clouds are also carried by the wind from west to east, forming a circle as well. The spectral data the researchers are working with also suggests that droplets of minerals such as corundum – the mineral that make up rubies and sapphires – also form on the night side of the planet. “So it could be raining liquid gems on WASP-121b’s night,” said a statement from the Max Planck Institute for Astronomy.

WASP-121b to be studied with James Webb Space Telescope

The discovery of an exoplanet is far from complete: “To better understand this planet, we will observe it with the James Webb Space Telescope within its first year of operation,” explains Michal-Evans, lead author of the study. The telescope, which was launched in late 2021, observes the universe in the infrared range and aims to help the team determine, among other things, the amount of carbon in WASP-121b’s atmosphere. In this way, the researchers want to gain information about how and where exoplanets formed. The measurement must be precise enough that researchers can obtain information about wind speed at different heights in the atmosphere.

Recently, several new discoveries have been made around exoplanets: a third exoplanet has been discovered around the nearest star to Earth, Proxima Centauri, exoplanet TOI-2109b is even hotter than WASP-121b and iron melts on exoplanet WASP-76b. Rising and falling. As the rain floor. (tab)