Using the European Southern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have discovered the heaviest element ever found.
The element (barium), whose discovery was announced Thursday in the Journal of Astronomy and Astrophysics, is the heaviest element ever found in the atmosphere of an exoplanet.
The researchers were surprised to discover high-altitude barium in the atmosphere of the super-hot gas giants (WASP-76 b) and (WASP-121 b), two exoplanets, and this unexpected discovery raises questions about the shape of these strange atmospheres.
“The puzzling and counterintuitive part is: why is there such a heavy element in the upper atmospheres of these planets,” says Tomas Azevedo Silva of the University of Porto and Instituto Astrofísica e Ciencias de España (IA) in Portugal, who led the study.
The two planets (WASP-76 b) and (WASP-121 b), are not ordinary exoplanets, and both are known as the very hot Jupiter as they can be compared in size to Jupiter while their surface temperatures are very high and exceed 1000 degrees Celsius, and this is due to their proximity to host stars
It also means that it only takes a day or two to orbit each star, which gives these planets rather strange features. On WASP-76 b for example, astronomers think it rains iron.
However, scientists were surprised to find barium, which is 2.5 times heavier than iron, in the upper atmospheres of the two planets.
“Due to the high gravity of the planets, we would expect heavy elements such as barium to rapidly fall into the lower atmosphere,” explains co-author Olivier Demangon, also a researcher from the University of Porto.
“This was somehow an accidental discovery,” Azevedo Silva says. “We weren’t expecting or looking for barium in particular and had to check if this was really coming from the planet because it hadn’t been seen in any exoplanet before.”
The fact that barium has been detected in the atmosphere of super-hot Jupiters suggests that this class of planets may be even more exotic than previously thought.
And although we sometimes see barium in our skies, as the brilliant green in fireworks, the question for scientists is: What natural process could cause this heavy element at such high altitudes in these exoplanets. “At the moment, we’re not sure about the mechanisms,” says Dimanjohn.