In situ and remote observations of the ultraviolet footprint of the moon Callisto by the Juno spacecraft

作者：J. Rabia, Vincent Hue, Corentin Louis, Nicolás André, Quentin Nénon, J. R. Szalay, R. Prangé, Laurent Lamy, P. Zarka, B. Collet, F. Allegrini, R. W. Ebert, T. K. Greathouse, Bertrand Bonfond, G. R. Gladstone, A. H. Sulaiman, W. S. Kŭrth, J. E. P. Connerney, P. Louarn, E. Penou, A. Kamran, Daniel Santos‐Costa, Rohini Giles, Joshua A. Kammer, M. H. Versteeg, S. J. Bolton · 发表于：Nature Communications · 年份：2025 · DOI：10.1038/s41467-025-62520-4 · 被引用次数：2 · 研究领域：Astro and Planetary Science、Planetary Science and Exploration、Stellar, planetary, and galactic studies

Abstract Jupiter exhibits peculiar multiwavelength auroral emissions resulting from the electromagnetic interactions of Io, Europa, and Ganymede with the magnetospheric plasma flow. Characterizing the faint auroral footprint of the fourth Galilean moon, Callisto, has always been challenging because of its expected weakness and its proximity to Jupiter’s bright main aurora. Here, we report on unusual magnetospheric conditions that led to an equatorward shift of Jupiter’s main auroral oval unveiling the auroral footprints of the four Galilean moons in a single observation. Remote observations by the Juno spacecraft reveal a double-spot structure, characteristic of the footprints of the other three moons, with a maximum ultraviolet brightness of 137 $$\pm$$ ± 15 kR. Concurrent observations within Callisto’s flux tube reveal field-aligned electrons with a characteristic energy of 10 keV, depositing an energy flux of 55 mW.m -2 in Jupiter’s atmosphere. The electron properties are consistent with the triggering of radio emissions with intensities lower than 5 × 10 -18 W.m -2 .Hz -1 .