The following document lists the file abstract/PDROSSAR_JUPITER.abs
from catalogue VI/111.
A plain copy of the file
(without headers/trailers) may be downloaded.
The observations of the infrared aurorae of Jupiter in the 7-13 micron range allow us to investigate how the atmosphere radiates the auroral energy brought by the precipitating particles accelerated in the magnetosphere. The total auroral power input has been estimated from the Voyager/UVS experiment and HST observations (Dols et al, 1992) of the order of 10 TW. The energy loss occurs mainly in the infrared, from the radiation of hydrocarbon bands in the 7-13 micron range. Estimates of the auroral power output from Voyager/IRIS experiment show an apparent larger power of the order of 40 TW (Drossart et al, 1993). The excess power could be due to some ionospheric mechanisms like the Joule heating observed in Earth atmosphere. Unfortunately, the infrared spectrum responsible of the excess emission is almost not accessible from the ground: most of the emission comes from the nu4 band of CH4 at 7.7 micron, and from the nu5 band of C2H2 at 13.6 micron. Therefore, ISO is the first experiment which has the capacity of measuring accurately the spectrum of Jupiter in this range. Despite a limited spatial resolution, the SWS aperture is able to scan Jupiter auroral regions and to discriminate the auroral excess energy within several hydrocarbon bands. Another interest is to measure some hydrocarbon bands which have been detected only tentatively in the auroral regions (Kim et al, 1985), like C6H6 and C3H4, due to the limited spatial resolution of Voyager/IRIS. SWS, with a 4 times higher spectral resolution will be able to identify more accurately the auroral emissions. ISO will be the only instrument operating in this spectral range. The Galileo orbiter has no spectrometer working at longer wavelengths than 5 micron: the ISO observations are therefore complementary of the auroral observations which will be performed with Galileo/Near Infrared Mapping Spectrometer in the 2-4 micron range, between 1996 and 1998.