EUV Spectra of Jupiter from EUVE Satellite and EUVS Rocket

We present EUV spectra of Jupiter taken during the week of the comet Shoemaker-Levy 9 impacts, July 16--22, 1994. The total EUVE exposure time during the impact week was >120 ksec, with comparable exposures times both before and following the impacts. The 7--76 nm data from this period show a transient enhancement in the jovian 58.4 nm signal of neutral helium, which has been interpreted as solar 58.4 nm emissions reflected from the high-altitude remains of impact plumes (Gladstone et al., Science, 268, 1595, 1995). This plume material is expected to contain many other species at their deep-atmosphere mixing ratios. Although no other transient EUV emissions were detected from Jupiter with EUVE, we will present upper limits derived for the mixing ratios of several important but difficult to detect species, such as neon. In addition to the EUVE data, we also flew an EUV spectrometer (EUVS) on a sounding rocket, which obtained a 224 second exposure of Jupiter and the Io Plasma Torus on July 20, 1994. The Io Plasma Torus data have been presented elsewhere (Stern et al., Geophys. Res. Lett., 22, 1837, 1995). The EUVS spectrum covers the wavelength range 82--114 nm, and contains many features from the Lyman and Werner bands of H_2 emitted in Jupiter's auroral regions. We will present an analysis of these auroral emissions, with comparison to Astro-1 and Astro-2 results for the same wavelength range.