A new auroral structure on Jupiter: Jupiter's auroral bridge

Abstract

The intense auroral emissions of Jupiter are well studied. However, there is still a lot of information to discover. In this study, a structure of the northern hemisphere has been analysed. It has been named Jupiter’s auroral bridge since it connects the duskside main emission and the polar region. This structure is not always visible. Three cases with different characteristics were therefore selected in order to analyse the behaviour of this feature. This study is based on the ultraviolet images obtained by the Space Telescope Imaging Spectrograph (STIS) on board the Hubble Space Telescope (HST). The analysis required mapping the locations where this structure appears in the ionosphere towards the equatorial plane in the magnetosphere. To do so, two different methods of mapping were considered. This data could help to infer the origin of this auroral emission. Moreover, in order to estimate its contribution to the total emitted power, the power radiated by the auroral bridge was also analysed. During this study, it was observed that this structure moves equatorward with time and that it pulsates. The periodicity was consequently estimated. This study offers some preliminary results which will be used to characterise Jupiter’s auroral bridge; a structure which has been little studied so far.