Infrared observations of Jovian aurora from Juno's first orbits: Main oval and satellite footprints

Abstract

The Jovian Infrared Auroral Mapper (JIRAM) is an imager/spectrometer on board NASA/Juno mission for the study of the Jovian aurorae. The first results of JIRAM's imager channel observations of the H<SUB>3</SUB><SUP>+</SUP> infrared emission, collected around the first Juno perijove, provide excellent spatial and temporal distribution of the Jovian aurorae, and show the morphology of the main ovals, the polar regions, and the footprints of Io, Europa and Ganymede. The extended Io "tail" persists for 3 h after the passage of the satellite flux tube. Multi-arc structures of varied spatial extent appear in both main auroral ovals. Inside the main ovals, intense, localized emissions are observed. In the southern aurora, an evident circular region of strong depletion of H<SUB>3</SUB><SUP>+</SUP> emissions is partially surrounded by an intense emission arc. The southern aurora is brighter than the north one in these observations. Similar, probably conjugate emission patterns are distinguishable in both polar regions.