1/ Out of #scifi ! Using our Very Large Telescope, astronomers have mapped the 3D structure of an exoplanet's atmosphere like never before, revealing a complex weather pattern.
➡️ https://www.eso.org/public/news/eso2504/
The atmosphere of WASP-121b has layers of iron, sodium and hydrogen moving at different speeds, including a powerful jet stream at the equator.
But how did astronomers figure this out? Keep reading...
🎨 ESO/M. Kornmesser
2/ As the planet crosses in front of its host star, atoms in the planet's atmosphere absorb specific colours of the star's light. These missing colours tell us how fast the atoms are moving and how deep in the atmosphere they are.
The weather in WASP-121b is fascinating:
- There is a deep layer of iron wind blowing away from the point where the star is directly overhead.
- Above it there's a fast jet stream of sodium that gets faster and hotter as it crosses the planet's day side.
- Finally, there's an upper layer of hydrogen wind blowing outwards.
WASP-121b is tidally locked –– one side always faces its host star –– and these results tell us how energy is transferred from the day to the night side.
🎨 ESO/M. Kornmesser
3/ These measurements were done with ESPRESSO, a extremely precise spectrograph at our VLT.
But the signals studied in this work were so faint that a single telescope wasn’t enough. So the team fed the light captured by all four 8.2 m telescopes of the VLT into ESPRESSO!
Who knows what other exotic weather patterns we’ll find in other planets?
