Titan's stratospheric zonal wind, temperature, and ethane abundance a year prior to Huygens insertion

Saturn's satellite, Titan, may have stratospheric winds up to ∼210 m/s, circling Titan in ∼1 terrestrial day compared to its 16‐day rotation. Theoretical models explaining such super‐rotating winds are not well constrained by observations of Titan or a similar slow rotator, Venus. We report measurements taken in December 2003 of zonal wind near Titan's equatorial region, including the Cassini Huygens probe entry latitude. Super‐rotating prograde zonal winds of 190 ± 90 m/s near 220 km altitude are found from Doppler‐shifted C2H6 gas emission near 12 μm, confirming high wind velocity even near the equator. Stratospheric temperature constraints and ethane abundance (8 ± 3 ppm) also are retrieved. Results are not inconsistent with earlier measurements and with recent Cassini CIRS results, but indicate possible variations between Titan's hemispheres. Differences in east and west C2H6 spectral line shapes can be accounted for by different vertical distributions of either C2H6 abundance or temperature or by unidentified dynamical effects.