JWST has mapped Uranus’s upper atmosphere in 3D

New JWST observations of Uranus reveal that its upper atmosphere is still cooling, with an average thermospheric temperature of ~426K, continuing a trend observed since the early 1990s.

More interestingly, two bright auroral bands have been detected near its magnetic poles, with a distinct depletion in emission and ion density between them. This feature is likely linked to transitions in magnetic field lines — similar to darkened auroral regions observed at Jupiter.

However, Uranus’s magnetosphere is uniquely tilted and offset from its rotational axis, creating asymmetric magnetic geometries that affect how charged particles move through the upper atmosphere.

These observations offer a rare opportunity to study magnetosphere–atmosphere coupling and vertical energy transport in a non-dipolar magnetic environment.