WASP-43 b is a "hot Jupiter" type exoplanet. Similar in size to Jupiter and mainly composed of hydrogen and helium, it is much hotter than the gas giants of our own Solar System, due to its proximity to its star, i.e.: less than 1/25e of the distance between Mercury and the Sun.
Mid-infrared measurements obtained with the Webb Telescope’s MIRI instrument, combined with 3D climate models and other observations, suggest thick, dense clouds on the night side, clear skies on the day side.
Variation in the surface temperature of the gas-giant exoplanet WASP-43 b
This graph shows the variation in surface temperature of the gas-giant exoplanet WASP-43 b. The day side has an average temperature of around 1250°C, while that of the night side is around 600°C. This temperature difference can be explained by the fact that the planet always faces its star the same way, but also by other factors such as wind speed and the presence of clouds. Complex 3D atmospheric models reveal that the planet’s hottest point is not directly beneath the star, but shifted by around 7 degrees to the east due to strong equatorial winds moving warm air horizontally before it can radiate energy back into space. These winds transport the heat to the night side, although the latter still appears too cold, probably due to clouds trapping the thermal energy.
Translated with DeepL.com (free version) Crédit : NASA, ESA, CSA, Ralf Crawford (STScI) ; Science : Taylor J. Bell (BAERI) ; Joanna Barstow (Open University); Michael Roman (University of Leicester)
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Supersonic equatorial winds mixing atmospheric gases around planet Wasp-43b reach up to 8,000 km/h.
This study demonstrates the advances in exoplanet science made possible by JWST’s unique ability to measure temperature variations and detect atmospheric gases hundreds of light-years away.
Read this article in full :
- In French, on the LESIA website :
Des chercheurs cartographient la météo d’une exoplanète grâce au télescope James Webb
- On the Webb Space Telescope website [in English]. :
NASA’s Webb Maps Weather on Planet 280 Light-Years Away
Reference
This work was published in the journal Nature Astronomy on April 30, 2024. : "Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b"