DPS 35th Meeting, 1-6 September 2003
Session 12. Titan II
Oral, Chairs: H. G. Roe and M. H. Stevens, Wednesday, September 3, 2003, 1:30-3:00pm, DeAnza I-II

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[12.07] VLT/NACO disk-resolved observations of Titan: the trailing hemisphere and a polar feature

A. Coustenis, E. Gendron, P. Drossart, M. Combes, M. Hirtzig, F. Lacombe, D. Rouan, C. Collin, S. Pau (LESIA, Paris-Meudon Observatory, France), A.M. Lagrange (Lab. Astrophysique, Obs. de Grenoble, France), P. Rannou (S.A., Univ. Paris VI - Univ. de Versailles, France), A. Negrão (S.A., Univ. Paris VI - Univ. de Versailles, France and LESIA)

Titan was observed in the near-infrared during an exploratory observing campaign in November 2002 with the new Nasmyth Adaptive Optics System (NACO) at the European Southern Observatory Very Large Telescope (ESO/VLT) 8-m UT4 unit in Chile. Our data were taken with NACO's spectro-imager, called CONICA. CONICA is equipped with a 1024x1024 pixel InSb array detector sensitive from 1 to 5 micron. The nominal pixel size is 0.013 arcsec. The images were acquired in several narrow-band filters (1.04, 1.08, 1.09, 1.24, 1.28, 1.64, 1.75, 2.12, 2.17 micron) and they cover three different phases of Titan at 80, 190 and 212 of SEP longitudes (November 20, 25 and 26 respectively). The reduced data are of excellent quality and in most cases of unparalleled resolution and contrast. They exhibit atmospheric phenomena and surface features seen in great detail. Indeed, we have obtained contrasts of 100 1.28 surface images of Titan's trailing hemisphere thus recovering an excellent cartography there. We have also observed a bright (by 70 darker areas) atmospheric feature at Titan's South Pole with a fast movement around the pole. This feature is visible at 2.12 micron but disappears at 2.17 micron. This could be indicative of the presence of a polar cloud tracer (or "vortex") on Titan at precise altitudes in the atmosphere. We will present the first results of our analysis of the data (Gendron et al., 2003) and describe the phenomena observed. References: Gendron, E., Coustenis, A., P. Drossart, M. Combes, M. Hirtzig, F. Lacombe, D. Rouan, C. Collin, S. Pau, A.-M. Lagrange 2003. VLT/NACO adaptive optics imaging of Titan. Astron. Astroph., in press.

If you would like more information about this abstract, please follow the link to http://www.lesia.obspm.fr/planeto/Titan/Web_OA_Titan.htm. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: athena.coustenis@obspm.fr

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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.