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M.A. Barucci, C. de Bergh, J. Romon (DESPA/Obs. Paris), J.G. Cuby (ESO, Chile), A. Le Bras (DESPA/Obs. Paris), B. Schmitt (Lab. Planet., Grenoble)
Centaur and Trans-Neptunian objects contain important information on the formation and evolution of the Solar System.
To study the surface composition of these faint and elusive objects, we have started an observational program at ESO-VLT with the infrared spectrometer ISAAC. The observations were made with the Antu telescope (the first 8 meter telescope of the VLT built on Mount Paranal, Chile). The spectra were recorded with ISAAC at low resolution in the J, H and K regions. These are the spectral ranges where the most diagnostic features of ices are present. The observations, initially made at a resolution of 500, were degraded in order to increase the S/N ratio.
We obtained near-infrared spectra of two Centaurs: 1950 GO, now named 8405 Asbolus, and 1995 DW2 and of the Trans-Neptunian 1996 TP66. At present only 8405 Asbolus spectra have been reduced and interpreted. The spectra show a rather featureless behaviour with, in particular, no absorption due to water ice. We have combined our near-infrared spectrum with a visible spectrum, and have performed some preliminar spectral modelling attempts.