James Webb Produced First 3D Map of Uranus’s Upper Atmosphere
Credit: NASA
The James Webb Space Telescope has created the first three-dimensional map of the auroras on Uranus. To do this, an international team of astronomers observed this distant planet in the Solar System for almost its entire rotation period—approximately 17 hours. This allowed them to obtain unique spectral data on the planet’s upper atmosphere at altitudes of up to several thousand kilometers above the clouds, significantly shedding light on its structure.
During 15 hours of observations, the NIRSpec spectrograph was able to detect the faint glow of molecules at altitudes up to 5,000 km above the clouds. For the first time, the temperature and ion density were measured in detail: the maximum temperature was at 3,000–4,000 km, and the maximum ion density was around 1,000 km. Two bright auroral bands were discovered near the magnetic poles and a zone of reduced emission between them—similar structures previously observed on Jupiter.
Uranus’s magnetic field is unique: tilted by 60° and offset from the planet’s center, causing auroras to move across the surface in complex trajectories. New data has made it possible to trace how magnetic lines guide charged particles and shape the structure of the atmosphere.
But most importantly, the data obtained opens up new possibilities for understanding the physics of ice giants, their magnetospheres, and auroras, which differ significantly from similar phenomena on other planets. This is important not only for studying distant planets in our solar system but also for understanding processes on exoplanets far out in the universe.
