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F. M. Flasar (NASA/GSFC), CIRS Investigation Team
We summarize results on temperatures, winds, and composition of the Saturn system from measurements by the Composite Infrared Spectrometer (CIRS) in the first year of the Cassini tour. Saturn's south polar stratosphere is surprisingly warm. Low-latitude zonal winds decay strongly with height in the stratosphere, and this could partially account for the smaller equatorial velocities reported from recent Hubble (and Cassini) images, compared to those derived earlier from Voyager. However, the features tracked in the later set would have to be more than 130 km higher in the stratosphere, if altitude effects alone are to explain the differences. Temperatures observed in Saturn's rings, at different phase and emission angles, suggest that the ring particles are slowly rotating. Diurnal temperature curves for Phoebe, Iaptetus, and Enceladus imply thermal inertias that are approximately half those of the Galilean satellites, indicating that the material just below the surfaces of the saturnian satellites is less consolidated. Titan's stratospheric zonal winds are greatest in its winter northern hemisphere. Together with the anomalous concentrations of several organic compounds in the north-polar region, this suggests an isolation of north polar air from that at low and southern latitudes, much as occurs in the winter polar regions of Earth.
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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.