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Titan's stratospheric zonal wind, temperature, and ethane abundance a year prior to Huygens insertion
Author(s) -
Kostiuk T.,
Livengood T. A.,
Hewagama T.,
Sonnabend G.,
Fast K. E.,
Murakawa K.,
Tokunaga A. T.,
Annen J.,
Buhl D.,
Schmülling F.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023897
Subject(s) - titan (rocket family) , equator , venus , atmospheric sciences , latitude , geology , physics , environmental science , astrobiology , geodesy
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 C 2 H 6 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 C 2 H 6 spectral line shapes can be accounted for by different vertical distributions of either C 2 H 6 abundance or temperature or by unidentified dynamical effects.