The Ionosphere of Uranus as Revealed by JWST
Year: 2025
Type: article
Abstract: The first spectroscopic observations of Uranus by the James Webb Space Telescope were obtained in January 2023. Using these observations, we explored the physical properties of the planet's ionosphere through the analysis of near‐infrared spectra. We found that both the northern and southern aurora were present; confirmed by localized column density enhancements. The median ionospheric temperature across the disk was 415 13 K, which is at least 300 K lower than measured by Voyager 2 in 1986, making these the lowest temperatures ever recorded. Surprisingly, auroral temperatures are not elevated in the south, and are only enhanced by tens of Kelvin in the north, indicative of limited heating or very efficient transport away from the auroral regions. Significant non‐auroral ionospheric structure is observed, including a dark band aligned with the magnetic dip equator, revealing the first imprints of Uranus's magnetic field on its ionosphere.
Source: Geophysical Research Letters
DOI: 10.1029/2025gl118301
Institutions: Northumbria University, University of Leicester, Association of Universities for Research in Astronomy, Goddard Space Flight Center, Boston University, University of Reading, Adolfo Ibáñez University, Centre National de la Recherche Scientifique, Université Paris Cité, Aix-Marseille Université, Université Paris Sciences et Lettres, Observatoire de Paris, Sorbonne Université, LIRA - Laboratoire d'instrumentation et de recherche en astrophysique
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $3,190
Awards: G103270039, A Consolidated Grant Proposal for Solar and Planetary Science, 2022 - 2025 Project 8: Observing currents within giant planet ionospheres, G2382751100, G256731684, G2916559141, A Consolidated Grant Proposal for Solar and Planetary Science at the University of Leicester, 2022 - 2025, Exploring the Giant Planet Energy Crisis with JWST, Fundamental Processes at Giant Planets in the Solar System and Beyond: Global heating and Saturn's Raining Rings
OpenAlex ID: W4416302853