The external region of the Solar System contains a vast population of small 
icy bodies, believed to be remnants from the accretion of the planets. The 
transneptunian objects (TNOs) and Centaurs (located between Jupiter and 
Neptune) are probably made of the most primitive and thermally unprocessed 
materials of the known Solar System.

In October 2006 we started a large programme (500 hours, PI M.A. Barucci) at 
the ESO-VLT Observatory to study the surface properties of TNOs and Centaurs 
by carrying out simultaneous visible and near-infrared spectroscopic 
observations  for about 50 objects with various dynamical properties.

The aim of this programme is to unambiguously detect and quantify the main icy 
compounds present on the surface of the selected TNOs and constrain their 
composition with a high accuracy. In greater details, we: i) search for the 
spectral signatures of compounds such a H2O, CH4, CH3OH, N2, NH3, CO2, and CO 
ices; ii) search for the presence of hydrated minerals; iii) attempt to 
discriminate between the states of crystalline and amorphous H2O ice on their 
surface; and iv) investigate the presence of organics and silicates on the 
surface. For a few objects, complementary observations in polarimetry and 
photometry were also carried out to better investigate the surface 
characteristics.
I will present and discuss the first results obtained during the first year of 
observations of our programme.