Atmospheric structure of WASP-43 b reveals distinct cloud distribution across different phases

Researchers have analyzed the complex atmospheric structure of the hot Jupiter WASP-43 b to better understand how clouds influence planetary climates. By combining atmospheric dynamics with cloud microphysics, the study maps out clear and cloudy regions across the planet's dayside and nightside. These findings provide a new baseline for comparing observed thermal profiles and emission spectra with complex models.

Star system: WASP-43 | Distance from the Sun: 284 light years

WASP-43 b is a hot Jupiter, a type of large gas giant planet that orbits very close to its host star. Because these planets are tidally locked, one side constantly faces the star while the other remains in permanent darkness. This extreme environment creates intense weather patterns, including powerful winds that carry heat around the globe. Clouds play a critical role in these atmospheres by reflecting sunlight and trapping heat, but they are difficult to model because they form and disperse in response to shifting temperatures and chemical compositions.

To better understand this behavior, investigators created a comprehensive modeling system that simulates both the movement of gas and the formation of clouds. They used a three-dimensional model to calculate the overall atmospheric flow, then applied a microphysical model to predict where specific minerals and silicates condense into cloud particles. Finally, they produced synthetic light spectra to compare against actual observations from the James Webb Space Telescope. This layered approach allows for a more detailed look at how different components of the atmosphere interact.

The analysis indicates that the cloud distribution on WASP-43 b is not uniform. The nightside of the planet is largely covered in clouds, which likely impacts how heat escapes into space. In contrast, the dayside appears clear at the level of the photosphere, the layer where light originates. The regions between these two, known as the morning and evening limbs, feature patchy cloud cover. While the current model accurately predicts the presence of five different cloud species, it currently overestimates the total thickness of these clouds, suggesting that further refinements to the modeling process are needed.

Key findings
WASP-43 b possesses a cloudy nightside and a clear dayside at the photosphere level.
Morning and evening limbs of the planet contain patchy cloud formations.
The model successfully predicts the condensation of five distinct cloud species including silicates.
Calculated cloud opacity is currently higher than what is observed in telescope data.

Scientific study

The coupled impacts of atmospheric dynamics and cloud microphysics on hot Jupiter atmospheres. I. An application to WASP-43b (external link)