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S.J. Kim (Kyunghee U. ), L.M. Trafton (U. Texas), T.R. Geballe (Gemini Obs.), Y.S. Lee, J.H. Kim (Kyunghee U. ), Kyunghee University Team, University of Texas Collaboration, Gemini Observatory Collaboration
We have analyzed the meridional 2 \mum spectra of Jupiter and Saturn, which were observed in July, 1999 at the UKIRT telescope with CGS4. The spatially resolved spectra provide us with an opportunity to study the latitudinal variation of their 2 \mum (H2)2 dimer absorption features. We measured the equivalent widths vs latitude of two prominent dimer absorption features near 2.122 \mum. The equivalent widths were then compared with an ab initio model of the (H2)2 dimer, which has been constructed by modifying a quantum mechanical model of Schaefer and McKellar (1990. Z. Phys. D - Atoms, Molecules and Clusters. v. 15, p. 51.), in order to extract the ortho/para ratio of H2 and its latitudinal variation, expected from dynamical processes. The latitudinal variation of the 2 \mum (H2)2 absorption has also been compared with that for adjacent CH4 line absorption features and the pressure-induced H2-H2 absorption for each planet. There is remarkable agreement, especially between the dimer and H2-H2 absorption, except for a pronounced rise in CH4 absorption at Jupiter's limb. The implications and preliminary results derived from these comparisons will be presented. We also report a tentative detection of the 2 \mum H2-N2 dimer feature on Titan near 2.122 \mum, and a possible temporal variation of its absorption within a day suggesting abrupt weather/cloud change.
The author(s) of this abstract have provided an email address for comments about the abstract: sjkim1@khu.ac.kr