Letter to the Editor

A new VLT surface map of Titan at 1.575 microns

¹ European Southern Observatory, Alonso de Cordova 3107, Santiago 19, Chile
² Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
³ Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721-0065, USA

Corresponding author: M. Hartung, mhartung@eso.org

Received: 15 April 2004
Accepted: 12 May 2004

Abstract

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 [CITE] 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.