HUBBLE-SPACE-TELESCOPE GODDARD HIGH-RESOLUTION SPECTROGRAPH H2 ROTATIONAL SPECTRA OF JUPITER AURORA

We have observed the emission spectrum from Jupiter's north auroral atmosphere with 0.57 angstrom spectral resolution over 1204-1241 angstrom. Bright emissions have been detected from 50-degrees to 60-degrees latitude at locations consistent with 6 to 30 R(J) auroral ovals, with much fainter emissions away from the auroral ovals. The emission spectrum is well fitted by both laboratory spectra and theoretical models of optically thin electron excited H-2, with added Doppler-broadened Lyalpha emission. The observed Lyalpha emission wings extend more than 1 angstrom from line center and appear correlated in strength with the H-2 brightness. Individual rotational lines in the H-2 Werner band system are resolved, allowing a determination of the H-2 rotational temperature at the altitude of the emission. We derive best-fit temperatures from 400-450 to 700-750 K, with the auroral emission layer temperature changing either across the auroral oval or over several days' time. These observations demonstrate for the first time the ability to measure the observed rapid H-2 temperature variations across Jupiter's auroral atmosphere.