James Webb Space Telescope sees Jupiter moons in a new light
With its sensitive infrared cameras and high-resolution spectrometer, the James Webb Space Telescope (JWST) is revealing new secrets of Jupiter's Galilean satellites, in particular Ganymede, the largest moon, and Io, the most volcanically active.
A spectroscopic map of Ganymede (left) derived from JWST measurements shows light absorption around the poles characteristic of the molecule hydrogen peroxide. A JWST infrared image of Io (right) shows hot volcanic eruptions at Kanehekili Fluctus (center) and Loki Patera (right). The circles outline the surfaces of the two moons. (Image credit: Samantha Trumbo, Cornell [Ganymede], and Imke de Pater, UC Berkeley [Io])
JWST measurements obtained in November 2022 overlaid on a map of Io's
surface. Thermal infrared measurements (left) show a brightening
of Kanekehili Fluctus, a large and, during the observation
period, very active volcanic area on Io. Spectral measurements
(right
) show forbidden infrared emissions from sulfur monoxide centered on the volcanic area. The coincidence confirms a theory that SO is produced in volcanic vents and, in the very thin atmosphere of Io, remain around long enough to emit the forbidden line that would normally be suppressed by collisions with other molecules in the atmosphere.
Image credit: Chris Moeckel and Imke de Pater, UC Berkeley; Io map courtesy of USGS
References:
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Volume 128, Issue 8
e2023JE007872. https://doi.org/10.1029/2023JE007872.