Observation of auroral “raindrops” in Jupiter's polar region by Juno-UVS

Juno-UVS has observed Jupiter's FUV auroral emissions during 19 close flybys following Juno orbital insertion on 5 July 2016. Each perijove provides a different snapshot of the Jovian auroral emissions recorded at different system III longitude and local time conditions. During PJ6 (19 May 2017), UVS recorded several transient auroral features located within Jupiter's northern polar auroral region. These auroral “raindrops” are characterized by bright spots of H2 emission (typically ~100 kR), which expand into concentric circles over tens of seconds, and seem to appear most often at local times close to noon. In this study we characterize where the raindrops occur in Jupiter's polar region, their spectral characteristics, and their typical expansion rates.