A new VLT surface map of Titan at 1.575 microns

We present a first high contrast 1.575 micron surface map of Titan, that is haze corrected by simultaneously imaging the stratospheric layer. At visible and most near-infrared wavelengths, the methane rich atmosphere completely obscures the surface; only in a few narrow wavelength windows does the atmosphere become optically thin. One of the most convenient windows (Griffith et al. 2003) lies at 1.58 μm, adjacent to the methane absorption feature at 1.62 μm. Our data span seven consecutive nights, resulting in phase coverage of 275° in longitude. The images were taken with NAOS-CONICA adaptive optics system at the VLT, using the recently commissioned Simultaneous Differential Imager mode (SDI). The combination of adaptive optics and simultaneous imaging through three filters sampling the methane absorption at 1.6 micron reveals extraordinary details of Titan's surface. Providing views of Titan's surface at high resolution (60 mas) is of particular topical importance, since the Cassini-Huygens mission is currently approaching the Saturn system and the Huygens probe will enter Titan's atmosphere in early 2005.

[1]  David Mouillet,et al.  NAOS, the first AO system of the VLT: on-sky performance , 2003, SPIE Astronomical Telescopes + Instrumentation.

[2]  M. Kasper,et al.  Science with Adaptive Optics , 2005 .

[3]  Mark T. Lemmon,et al.  Titan's Surface, Revealed by HST Imaging , 1996 .

[4]  T. Fusco,et al.  Astrophysics Vlt/naco Adaptive Optics Imaging of Titan , 2022 .

[5]  T. Owen,et al.  Evidence for the Exposure of Water Ice on Titan's Surface , 2003, Science.

[6]  Anne-Marie Lagrange,et al.  NAOS-CONICA first on sky results in a variety of observing modes , 2003, SPIE Astronomical Telescopes + Instrumentation.

[7]  B. Krauskopf,et al.  Proc of SPIE , 2003 .

[8]  Donald T. Gavel,et al.  Titan: High-Resolution Speckle Images from the Keck Telescope , 1999 .

[9]  Andrew Wilson.  Huygens : science, payload and mission , 1997 .

[10]  Laurent M. Mugnier,et al.  Images of Titan at 1.3 and 1.6 μm with Adaptive Optics at the CFHT , 2001 .

[11]  E. Gendron,et al.  Spatially Resolved Images of Titan by Means of Adaptive Optics , 1997 .

[12]  D. Campbell,et al.  Radar Evidence for Liquid Surfaces on Titan , 2003, Science.

[13]  Bradford A. Smith,et al.  The Surface of Titan from NICMOS Observations with the Hubble Space Telescope , 2000 .

[14]  C. McKay,et al.  Titan's Clouds from Gemini and Keck Adaptive Optics Imaging , 2002 .

[15]  David Mouillet,et al.  First diffraction limited images at VLT with NAOS and CONICA , 2003, SPIE Astronomical Telescopes + Instrumentation.

[16]  A. Bouchez,et al.  Direct detection of variable tropospheric clouds near Titan's south pole , 2002, Nature.