Detection of barium in the atmospheres of WASP-76b and WASP-121b

ESO have put out a press release reporting the discovery of barium in the atmospheres of ultra-hot Jupiters WASP-76b and WASP-121b, based on observations with the ESPRESSO spectrograph on ESO’s Very Large Telescope. Barium is the heaviest element so far detected in an exoplanet.

“The puzzling and counterintuitive part is: why is there such a heavy element in the upper layers of the atmosphere of these planets?” says Tomás Azevedo Silva, lead author of the paper.

This artist’s impression shows an ultra-hot exoplanet, a planet beyond our Solar System, as it is about to transit in front of its host star. When the light from the star passes through the planet’s atmosphere, it is filtered by the chemical elements and molecules in the gaseous layer. With sensitive instruments, the signatures of those elements and molecules can be observed from Earth. Using the ESPRESSO instrument of ESO’s Very Large Telescope, astronomers have found the heaviest element yet in an exoplanet's atmosphere, barium, in the two ultra-hot Jupiters WASP-76 b and WASP-121 b.

The work has been reported by dozens of newspapers and media websites, such as CNN and The Independent.