UV Emission from the Atmosphere of Jupiter After the S-Impact of Comet SL9
Abstract
The Hubble Space Telescope Faint Object Spectrograph was used to obtain a UV spectrum of the impact site of the S-fragment of comet SL9 approximately 45 minutes after the entry of the fragment into the atmosphere of Jupiter. This spectrum contains ultraviolet emission lines of neutral and ionized metals, including Mg I, Mg II, Fe I, Fe II, and Si I. Initial analyses of these data were presented by Noll et al. (1995, Science, 267, 1307) based on a pure solar resonance fluoresence synthetic spectrum and assuming collisional excitation at 1000 K, and by Carpenter et al. (DPS, Oct. 1995) who added non-resonance fluorescence and examined the possibility that some of the emission was caused by thermal excitation of metastable levels during the fireball and splashback phases of the impact. Since these line formation models do not fully account for the observed relative and absolute line fluxes, we have enhanced our model to include non-LTE effects, heating of the atmosphere due to infalling gas and dust, and the effects of multiple scatterings of photons as they attempt to exit the atmosphere of Jupiter at frequencies within optically thick lines. We compare the synthetic spectrum produced with this model to the observed spectrum and discuss the physical conditions and elemental abundances inferred from this comparison.
- Publication:
-
AAS/Division for Planetary Sciences Meeting Abstracts #28
- Pub Date:
- September 1996
- Bibcode:
- 1996DPS....28.2247C