JWST Discovers the Vertical Structure of Uranus' Ionosphere
Year: 2026
Type: article
Abstract: On 19 January 2025, the James Webb Space Telescope (JWST) program 5073 observed Uranus for almost a full rotation with NIRSpec. We present the first ever vertical ionospheric profiles of temperature, volumetric density and total emission. Temperature profiles peak between 3,000–4,000 km at all longitudes. Densities peak near 1,000 km with values up to (4.45 0.12) × , lower than predicted by 1‐D models. We identify two bright emission regions at 50–110W and 220–290W, near the auroral regions. A distinct emission and density depletion occurs between 190–240W, possibly reflecting magnetic topology influences, analogous to ionospheric dark regions at Jupiter. These results offer new insights into Uranus's upper atmosphere, confirm its long‐term cooling trend (426 2 K), and provide key constraints for ice giant ionospheric and magnetospheric modeling.
Source: Geophysical Research Letters
DOI: 10.1029/2025gl119304
Institutions: Northumbria University, Boston University, University of Reading
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
OpenAlex ID: W7130512815