Locating Active Volcanic Hotspots on Io Using Juno’s JIRAM

The Jovian Infrared Auroral Mapper (JIRAM) on the Juno spacecraft has provided unprecedented views of Io’s polar regions, enabling further understanding of how Io’s volcanoes may differ at high latitudes. Tidal heating, resulting from orbital eccentricity that is maintained by resonance with Jupiter’s moons Europa and Ganymede, is responsible for the widespread volcanism on Io. The pattern of volcanic activity is indicative of tidal dissipation in the interior.

During orbit 17, JIRAM obtained several images of Io in the L-band. We identified over 1000 possible hotspots by examining the 43 images individually. Mura et. al 2020 (Icarus, doi:2019.113607) stacked the same images together and also determined hotspot locations and brightnesses. In addition to analysing the images separately, we also determined the total brightness of each hotspot while Mura et al. (2020) noted only the peak brightness.

We detected all the volcanoes that Mura et al. (2020) detected plus others that we are currently investigating to determine if they are real or noise. We have included Galileo and New Horizons observations of Io to combine with the JIRAM findings to compare to tidal heating model predictions.