Discovery of H+3 and infrared aurorae at Neptune with JWST

Melin, H., Moore, L., Fletcher, L. N., Hammel, H. B., O'Donoghue, J. ORCID: https://orcid.org/0000-0002-4218-1191, Stallard, T. S., Milam, S. N., Roman, M., King, O. R. T., Rowe-Gurney, N., Thomas, E. E., Wang, R., Tiranti, P. I., Harkett, J. and Knowles, K. L. (2025) Discovery of H+3 and infrared aurorae at Neptune with JWST. Nature Astronomy, 9. pp. 666-671. ISSN 2397-3366 doi: 10.1038/s41550-025-02507-9

Abstract/Summary

Emissions from the upper-atmospheric molecular ion have been used to study the global-scale interactions of Jupiter, Saturn and Uranus with their surrounding space environments for over 30 years, revealing the processes shaping the aurorae. However, despite repeated attempts, and contrary to models that predict it should be present, this ion has proven elusive at Neptune. Here, using observations from the James Webb Space Telescope, we detect at Neptune, as well as distinct infrared southern auroral emissions. The average upper-atmosphere temperature is a factor of two cooler than those derived 34 years ago by Voyager 2, showing that the energy balance of this region is regulated by physical processes acting on a timescale shorter than both Neptunian seasons (40 yr) and the solar cycle.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/122175
Identification Number/DOI	10.1038/s41550-025-02507-9
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Springer Nature
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