Auroral electron energy estimation using the H/H2 brightness ratio applied to Jupiter

International audienceThe measurement of the H/H2 brightness ratio of giant planets' far-ultraviolet (FUV) aurora is a proxy for precipitating soft (a few 10s keV) electrons. We investigate the relevance of this H/H2 indicator with the Jupiter auroral observations obtained by the Hubble Space Telescope. The H/H2 ratio does not show any clear relationship with the FUV color ratio which is sensitive to more energetic electrons. Compared to the same analysis applied for Saturn's aurora, the relationship for Jupiter mainly shows decreasing flux with increasing energy without acceleration features