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 planetâs ionosphere through the analysis of nearâinfrared H3+ ${\mathrm{H}}{3}^{+}$ spectra. We found that both the northern and southern aurora were present; confirmed by localized H3+ ${\mathrm{H}}{3}^{+}$ column density enhancements. The median ionospheric temperature across the disk was 415 Âą $\pm $ 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 nonâauroral ionospheric structure is observed, including a dark band aligned with the magnetic dip equator, revealing the first imprints of Uranusâs magnetic field on its ionosphere.
Observations from the Little Bunker
Last updated: February 28, 2026 02:12 PM
Atmospheric COâ
430.3 ppm
+17.9
ppm/year
Atmospheric CHâ
1946.47 ppb
+6.49
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year