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 the presence of thick, dense clouds on the night side, clear skies on the day side.
| Temperature variation on the surface of the gas giant exoplanet WASP-43 b This graph shows the temperature variation on the surface 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 difference in temperature is explained by the fact that the planet always presents the same face to its star, but also by other factors such as wind speed and the presence of clouds. Complex 3D atmospheric models reveal that the planet’s hottest spot is not directly beneath the star, but shifted about 7 degrees eastward due to strong equatorial winds moving hot air to the horizontal before it can radiate energy into space. These winds carry heat to the night side, although the latter still appears too cold, probably due to clouds trapping thermal energy. Credit: NASA, ESA, CSA, Ralf Crawford (STScI); Science: Taylor J. Bell (BAERI); Joanna Barstow (Open University); Michael Roman (University of Leicester) |
Supersonic equatorial winds mixing atmospheric gases around the planet Wasp-43b reach up to 8,000 km/h.
This study demonstrates advances in exoplanet science thanks to JWST’s unique capabilities to measure temperature variations and detect atmospheric gases hundreds of light years away.
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Reference
This work is the subject of a publication in the journal Nature Astronomy as of April 30, 2024: “Nightside clouds and disequilibrium chemistry on the hot Jupiter WASP-43b“
Scientific literacy webinar
Tuesday May 14, 2024, from 11 a.m. to 12 p.m., Lucas Teinturier, doctoral student at LESIA, gives a live seminar entitled: “The atmospheres of hot Jupiters: from their detection to their characterization“
Login link : https://us02web.zoom.us/j/88036208972
Recorded, this webinar will be visible, in replay, on the YouTube channel of the Paris Observatory – PSL, in the playlist “Scientific culture seminars”.
Last modified on May 7, 2024
