Free Astronomy Magazine January-February 2023

16 JANUARY-FEBRUARY 2023 ASTRO PUBLISHING by ESO - Juan Carlos Muñoz Mateos Heaviest element yet detected in an exoatmosphere U sing the European South- ern Observatory’s Very Large Telescope (ESO’s VLT), astronomers have dis- covered the heaviest ele- ment ever found in an exoplanet atmosphere — barium. They were sur- prised to discover bar- ium at high altitudes in the atmospheres of the ultra-hot gas giants WASP-76 b and WASP- 121 b — two exoplan- ets, planets which orbit stars outside our Solar System. This unexpected discovery raises questions about what these exotic atmospheres may be like. “The puzzling and counter- intuitive part is: why is there such a heavy element in the upper layers of the atmosphere of these planets?” says Tomás Azevedo Silva, a PhD student at the University of Porto and the Insti- tuto de Astrofísica e Ciências do Espaço (IA) in Portugal who led the study published in Astronomy & As- trophysics .