INFRARED EMISSIONS OF H-3(+) IN THE ATMOSPHERE OF JUPITER IN THE 2.1 AND 4.0 MICRON REGION

Infrared spectra of the Jovian atmosphere around 2.1 and 4.0 μm, measured using the NASA Infrared Telescope Facility at Mauna Kea Hawaii, are presented. The observations were made between 1990 February 6 and 8. In both spectral regions, features attributable to H3+ were visible. The intensity ratio of lines in the 2 and 4 μm regions measured from the northern auroral "hot spot" during the same night leads to a rovibrational temperature of 1100 ± 100 K for this molecular ion, close to a previous measurement of the rotational temperature of 1099 ± 100 K. This indicates that the upper energy levels are being populated by purely thermal processes, rather than by resonant energy exchange. The para-H3+ fractional abundance of 0.58 determined by previous workers is found to be consistent with this study. The time dependency of the H3+ emission phenomena is confirmed.