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Titan’s Rotation Reveals an Internal Ocean and Changing Zonal Winds

Iess, Luciano; Stiles, Bryan W.; Kirk, Randolph L. +6 more

Cassini radar observations of Saturn’s moon Titan over several years show that its rotational period is changing and is different from its orbital period. The present-day rotation period difference from synchronous spin leads to a shift of ~0.36° per year in apparent longitude and is consistent with seasonal exchange of angular momentum between th…

Temperature and Composition of Saturn’s Polar Hot Spots and Hexagon

Fletcher, L. N.; Irwin, P. G. J.; Teanby, N. A. +11 more

Saturn’s poles exhibit an unexpected symmetry in hot, cyclonic polar vortices, despite huge seasonal differences in solar flux. The cores of both vortices are depleted in phosphine gas, probably resulting from subsidence of air into the troposphere. The warm cores are present throughout the upper troposphere and stratosphere at both poles. The the…

The Dust Halo of Saturn’s Largest Icy Moon, Rhea

Coates, A. J.; Krupp, N.; Woch, J. +32 more

Saturn’s moon Rhea had been considered massive enough to retain a thin, externally generated atmosphere capable of locally affecting Saturn’s magnetosphere. The Cassini spacecraft’s in situ observations reveal that energetic electrons are depleted in the moon’s vicinity. The absence of a substantial exosphere implies that Rhea’s magnetospheric int…

Dynamics of Saturn's South Polar Vortex

Fletcher, Leigh N.; West, Robert A.; Porco, Carolyn C. +9 more

We present observations of Saturn's south polar vortex (SPV) showing that it shares some properties with terrestrial hurricanes: cyclonic circulation, warm central region (the eye) surrounded by a ring of high clouds (the eye wall), and convective clouds outside the eye. The polar location and the absence of an ocean are major differences. It also…