Evidence for Raman Scattering in HST FOS Spectra
Y. Bétrémieux, R. V. Yelle (CSP, Boston University)
Spectroscopic observations conducted May 5 and 6 1993 by HST along
Jupiter's central meridian at 65, 48, 6, 0, -6, -12, -25, -33, -48
and -65 degree planetographic latitude are analyzed to deduce the
latitudinal variation of acetylene abundance in Jupiter's upper
atmosphere. The measurements were obtained with the G190H grating
and Red detector combination of the FOS (Faint Object Spectrograph)
spanning 1573-2330Å at about 3.5Å resolution. The data were
corrected for scattered light, and careful modeling of the Line Spread
Function of the instrument was performed to accurately degrade the solar
spectrum obtained by SOLSTICE to that of the FOS. The I/F obtained
displayed features consistent with Raman scattering by molecular
hydrogen at wavelength of 2300, 2290, 2268, 2217, 2211 and 2124Å .
We have modified the DISORT radiative transfer code to incorporate
Raman scattering under the assumption that the Raman component of the
scattering phase function is isotropic. Rotational and vibrational
Raman scattering for the first few lowest energy rotational states
of molecular hydrogen are considered for this analysis.