36th DPS Meeting, 8-12 November 2004
Session 6 Titan I: Surface, Troposphere, etc.
Oral, Monday, November 8, 2004, 3:30-6:00pm, Clark

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[6.12] New Measurements of Titan Winds and More

T. Kostiuk (GSFC), T. A. Livengood (Challenger Ctr.), T. Hewagama, K. E. Fast (U.MD/GSFC), G. Sonnabend (NAS NRC/GSFC), J. Annen, D. Buhl (GSFC), F. Schmülling (U. Cologne), K. Murakawa (Subaru/NAOJ), A. Tokunaga (U.HI)

The direction and magnitude of global stratospheric wind on Titan was measured using the Goddard Space Flight Center Heterodyne Instrument for Planetary Wind And Composition, HIPWAC, at the National Astronomical Observatory of Japan Subaru Telescope on Mauna Kea, Hawaii. HIPWAC spectral resolving power of > 1,000,000 and the 0.36 arcsec diffraction limited FOV on Titan with the 8.2 m Subaru telescope enabled measurement of true emission line profiles of ethane near 12 microns on the East and West hemispheres of Titan. Differences in the line frequencies (Doppler shifts) determined the direction and magnitude of the wind. The line profiles were fit to retrieve ethane abundances and constraints on the thermal structure near 0.6 mbar pressures (~210 km). The near equatorial FOV positions overlapped the Huygens probe entry latitude. Analyses retrieve a prograde wind of 170 ± 93 m/s. Ethane abundance is 0.7± 0.3 x 10-5. Possible differences in temperatures between the two hemispheres may also be indicated. Discussion of uncertainties will be presented as well as comparisons to earlier IR heterodyne measurements and to expected results from measurements on Subaru during the descent of Huygens into Titan’s atmosphere on January 14, 2005 UT.

Work was supported by the NASA Planetary Astronomy Program.

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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.