31st Annual Meeting of the DPS, October 1999
Session 52. Outer Planet Chemistry Posters
Poster Group II, Thursday-Friday, October 14, 1999, , Kursaal Center

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[52.04] Latitudinal Variations of Jupiter in the UV (230-320 nm) as seen with the HST/Faint Object Spectrograph

S.G. Edgington, S.K. Atreya (U. Michigan), L.M. Trafton (U. Texas), R.A. West (NASA-JPL), J.J. Caldwell (York U.), R.F. Beebe (NMSU), A.A. Simon (Cornell U.)

During the time period of June 19--26, 1992, the Hubble Space Telescope Faint Object Spectrograph was used to observe Jupiter in the ultraviolet over the spectral interval of 150--330 nm. Analysis of these spectra at wavelengths shorter than 230 nm has been presented by Edgington et al. (Icarus, {\bf133}, 192--209, 1998), where it was shown that NH{3} and C{2}H{2} account for many of the features present in the spectra. This paper examines the Jovian UV spectra in the range 240--330 nm. These observations were taken both on and off the central meridian (CML) at a number of latitudes in the northern hemisphere, along with the Great Red Spot (GRS) and the nearby South Equatorial Belt (SEB). From these spectra, albedos were generated upon dividing by the UARS/SOLSTICE solar spectrum corresponding to the day of observation. Much of the structure thoughout this spectral range is due to Raman scattering, with the most prominent features corresponding to Fraunhaufer lines near 280 nm. However, the continuum of the albedo is lower than that of a pure Rayleigh-Raman scattering atmosphere, indicating the presence of aerosols or another continuum absorber. Furthermore, the spectral characteristics of the continuum show notable differences with latitude, with several spectra showing an increasing albedo at wavelengths beyond 280 nm, whereas many of the remaining spectra show a monotonic decrease with wavelength. We examine the variation of optical parameters, e.g. single scattering albedos and optical depths, with latitude by using various assumptions pertaining the atmospheric aerosols and composition. We also examine the implications of these observations on the abundances of several molecules possibly present in the Jovian atmosphere.

The author(s) of this abstract have provided an email address for comments about the abstract: sgest@engin.umich.edu

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