cassini-huygens/vims at t0 and ta: a taste of titanic things to come k. h. baines, b. buratti, p....

Cassini-Huygens/VIMS at T0 and Ta:

A Taste of Titanic Things to Come

K. H. Baines, B. Buratti, P. Drossart, C. Griffith, R. Jaumann, R. M. Nelson,

R. H. Brown, R. Clark, C. Sotin, T.Momary and the Cassini/VIMS Team

Salient Results from T0• Titan

– Surface

– Winds & Clouds

– EmissionsQuickTime™ and a

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Titan’s Surface Revealed at T0

- Crystal clear views of Titan’s surface achieved at several wavelengths in the near-infrared, particularly beyond 2.0 microns wavelength.

- Variety of surface features observed - Evidence for variety of substances--including organic-based materials

- No conclusive VIMS observational evidence yet for surface fluids- Specular reflection not observed on the approx. 2% of surface probed thus far

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Observations at T0

• Image 42.64 • HighRes in IR for some

observations• integration time between 160

ms and 640 ms.• Phase angle : 65°

Cloud Distribution/Windsfrom T0

- Single major cloud feature near South Pole - 88 degrees S. Latitude- ~400 km diameter- Tracked for 12 hours

- Several smaller, weaker clouds- Perhaps deeper cloudtops

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Titan: Multiple South Polar Cloud Features

Cloud Structure

Cloudtop: 20 ± 5 km

Opacity: ~2 at 2 m

Griffith Model

Titan Emissions

• Extensive atmosphere--10 times thicker than Earth’s--Glows for hundreds of kilometers above surface• Dayglow--Methane Fluorescence at 3.3 microns

– Extended atmosphere ~ 1/3 of Titan’s radius

• Nightglow discovered=> warm stratosphere > 160 K – Generated by primarily by C0, C02 and CH3D

Nightside Emissions Altitude Profile

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Titan Nightside 4.7-um Spectra

CH3D

CO2

Blue: Average over the Night limb

Red: Center of disk onnightside

CO, likely

Emission zone

CLOUD-TRACKED WINDS

Latest Results For Major South-Pole Cloud Feature (8/31/04):

0.5 ± 3 m/s, progradeBased on: (1) Motions relative to surface features (2) Motions from C-KernalsConsistent with current theories of Titan’s winds

This Week at Titan….

Titan’s surface and atmosphere will be imaged up to 100 times higherspatial resolution than previously achieved.

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VIMS will characterizethe surface and atmosphereat the Huygens probe landing site.