Simultaneous observations of the Saturnian aurora and polar haze with the HST/FOC

Abstract

Near simultaneous observations of the Saturnian H 2 north ultraviolet aurora and the polar haze were made at 153 nm and 210 nm respectively with the Faint Object Camera on board the post‐COSTAR Hubble Space Telescope. The auroral observations cover a complete rotation of the planet and, when co‐added, they reveal the presence of an auroral emission near 80°N with a brightness of about 150 kR of total H 2 emission. The maximum vertical optical depth at 210 nm is found to be located ∼5° equatorward of the auroral emission zone. The haze particles are presumably formed by hydrocarbon aerosols initiated by H 2 + auroral production. In this case, the 3 × 10 10 W of H 2 emission observed with the FOC, combined with the deduced haze optical depth requires an efficiency of aerosol formation of about 7%. This result indicates that auroral production of hydrocarbon aerosols is a viable source of high‐latitude haze.