As an Amazon Associate I earn from qualifying purchases.
Scientsts from the United States, Europe and China have actually utilized the Ultraviolet Spectrograph (UVS) onboard NASA’s Juno spacecraft to map comprehensive spot structures in Ganymede’s aurorae that parallel those seen in the world. Their findings suggest that the interaction in between electromagnetic fields and charged particles might be a universal engine for auroral lights, with ramifications for comprehending magnetospheres throughout the Solar System.
An artist’s principle of aurorae on Jupiter’s moon Ganymede. Image credit: NASA/ ESA/ G. Bacon, STScI/ J. Saur, University of Cologne.
Ganymede, the only moon understood to have its own intrinsic electromagnetic field, sustains a mini magnetosphere ingrained within that of Jupiter.
Its aurorae develop mostly from oxygen emissions at wavelengths of 130.4 and 135.6 nm, thrilled by speeding up electrons.
In brand-new research study, University of Liège scientist Philippe Gusbin and his collleagues examined ultraviolet observations of Ganymede taped on June 7, 2021, by the Juno spacecraft.
They determined several auroral spots on the moon’s leading, downstream hemisphere.
The spots have normal sizes of about 50 km and brightnesses reaching roughly 200 Rayleigh.
“Aurorae are likewise observed on Ganymede and are triggered by the rainfall of electrons in its thin oxygen environment,” Gusbin discussed.
“Observations of Ganymede’s aurorae previous to Juno were restricted by the spatial resolution of ground-based observations, and they might not deal with the small structures common of planetary aurorae.”
The morphology and scale of the functions look like auroral ‘beads’ seen at Earth before magnetospheric substorms and at Jupiter throughout so-called dawn storms.
The obvious lack of comparable spots in the southern hemisphere is credited to seeing geometry, although asymmetries associated with Ganymede’s position within Jupiter’s plasma disk can not be eliminated.
“The ‘beads’ have actually been observed in the aurorae of Earth and Jupiter, where they are connected to sub-storms and dawn storms, massive rearrangements of the magnetosphere that launch huge quantities of energy and produce extreme auroral activity,” stated Dr. Alessandro Moirano, a postdoctoral scientist at the University of Liège and the National Institute for Astrophysics in Rome.
The findings recommend that equivalent physical systems might run throughout magnetospheres in spite of large distinctions in scale and environment.
“Juno’s close observations of Ganymede lasted less than 15 minutes, and the spacecraft will never ever fly over Ganymede once again. We do not understand how typical these spots are or how they progress over time,” stated Dr. Bertrand Bonfond, an astrophysicist at the University of Liège.
“Fortunately, ESA’s Juice (Jupiter Icy Moons Explorer) objective is presently on its method to Jupiter, where it will show up in 2031, and will perform devoted observations of Ganymede.”
“The spacecraft is geared up with an ultraviolet spectrograph comparable to Juno’s: this will enable us to gather observations over longer durations, keep track of the development of Ganymede’s aurorae and, ideally, discover brand-new secrets.”
A paper on the findigns was released in the journal Astronomy & & Astrophysics
_____
A. Moirano et al2026. Juno’s high-spatial-resolution ultraviolet observations of Ganymede’s auroral spots. Restrictions on the magnetospheric source area. A&A 706, L16; doi: 10.1051/ 0004-6361/2025 58379
Learn more
As an Amazon Associate I earn from qualifying purchases.
