JWST Maps Dynamic Weather Systems on Ultra-Hot Exoplanet WASP-121 b

• Astronomers used the James Webb Space Telescope (JWST) to map atmospheric differences between the morning and evening twilight zones of the ultra-hot gas giant WASP-121 b.
• WASP-121 b is tidally locked, with a permanent dayside reaching 2500°C and a nightside at 725°C.
• The study utilized time-resolved observations during planetary transit, allowing researchers to track chemical and thermal shifts longitude by longitude.

Atmospheric Findings

• Evening Terminator: Characterized by extreme heat due to winds blowing from the dayside, resulting in higher carbon monoxide levels and the thermal dissociation of water molecules.
• Morning Terminator: Cooler than the evening side, retaining more water vapor.
• Discrepancy with Models: Observed signals were stronger than predicted by current atmospheric models, suggesting the presence of clouds made of vaporized minerals like silicates that block infrared radiation.

Scientific Significance

• Methodological Breakthrough: Researchers can now analyze exoplanet atmospheres as dynamic, non-uniform systems rather than averaged blobs.
• Future Outlook: The team plans to apply this technique to other ultra-hot exoplanets to build an atlas of alien weather patterns and refine atmospheric physics models.