BaSeL: A Library of Synthetic Spectra and Colours for GAIA

The Basel Stellar Library (BaSeL) is a library of synthetic spectra which has already been used in various astrophysical applications (stellar cluster studies, characterization and choice of the COROT potential targets, eclipsing binaries,...). This library could provide useful indications to 1) choose the best photometric system for the GAIA strategy by evaluating their expected performances and 2) apply systematically the BaSeL models for any sample of the GAIA targets. In this context, we describe one of the future developments of the BaSeL interactive web site to probe the GAIA photometric data: an automatic determination of atmospheric parameters from observed colours.