In space there are supermer tune and minine ple, hot Jupiter and even ultra -haze Jupiter, who circle so close around their star that their atmospheres are not comparable to our solar system. Tomás Azevedo Silva from the Universidade do Porto and his working group have now described two exoplanets in "Astronomy & Astrophysics", which still protrude even among the most exotic sky bodies: in their gas cover, the most difficult element drifted with barium clouds to date.
The 56th element in the periodic table thus joins a series of components that clearly distinguish the atmosphere of the two exoplanets from our Earth. In addition to barium, WASP-76b also contains calcium, titanium oxide and vanadium oxide, while WASP-121b contains vanadium, iron, chromium, calcium, sodium, magnesium and nickel. In certain regions of WASP-76b, which heat up less strongly, it could even rain iron.
WASP-76b and WASP-121b belong to the ultra-hot Jupiters and orbit their star at a very close distance in only 1.8 and 1.27 days, respectively, which heats them up extremely. Their surface temperature in each case is more than 1000 degrees Celsius. Nevertheless, it surprised the astronomers that they were able to detect barium. "Given the high gravity of the planets, we would expect heavy elements such as barium to fall quickly into the lower layers of the atmosphere," says co-author Olivier Demangeon.
"In a way, this was a" random "discovery," says Azevedo Silva. "We did not expect a barium or searched for it and had to make sure that it actually comes from the planet, since it has never been seen in an exoplanet before." For the working group, the question arises as to which natural process could lead to it, that this heavy element occurs at such large heights of the exoplanets. "At the moment we are not sure what mechanisms there are," says Demangeon.
Barium and co were detected using the ESPRESSO instrument on ESO's Very Large Telescope in Chile. At the same time, it was also possible to prove that the atmosphere around WASP-121b is slowly disappearing: it evaporates due to the influence of the nearby star. So the time of this ultra-hot Jupiter is limited.
