The Infrared Footprint Tracks of Io, Europa and Ganymede at Jupiter
Observed by Juno-JIRAM
Abstract
The electromagnetic coupling between the Galilean satellites at Jupiter
and the planetary ionosphere generates an auroral footprint, whose
ultimate source is the relative velocity between the moons and the
corotating magnetospheric plasma. The footprint can be detected in the
infrared L band (3.3-3.6 microns) by the Jovian InfraRed Auroral Mapper
(JIRAM) onboard the Juno spacecraft, which can observe the footprint
position with high precision. Here, we report the JIRAM data acquired
since August 27th 2016 until May 23rd 2022, corresponding to the first
42 orbits of Juno. The dataset is used to compute the average position
of the footprint tracks of Io, Europa and Ganymede. The result of the
present analysis can help to test the reliability of magnetic field
models, to calibrate ground-based observations and to highlight episodes
of variability in the footprint positions, which in turn can point out
specific conditions of the Jovian magnetospheric environment.