The energy the auroral electrons in Saturn's atmosphere : remote sensing and thermal consequences

Saturn’s north aurora has been observed between January and May 2011 with the Hubble Space
Telescope. The objective was to collect spatially resolved spectra at the different local time from dawn to dusk and compare them with laboratory or synthetic spectra. For this purpose, HST was
programmed to slew from mid-latitudes through the auroral oval up to above the limb while collecting data in the timetag mode. The spectra show signatures of absorption by hydrocarbons present above the peak of the auroral emission. The amount of absorption and implications in terms of penetration of the auroral electron beam into Saturn’s atmosphere will be discussed and compared with other determinations of the altitude of the aurora. The effects of the auroral heat import on the thermal structure of the atmosphere both at high and low altitudes will be examined in the light of these results.