Galactic globular clusters as a test for very-low-mass stellar models

We make use of the 'Next Generation' model atmospheres of Allard et al. and Hauschildt, Allard & Baron to compute theoretical models for low- and very -low-mass stars for selected metallicities in the range Z = 0.0002 to 0.002 . On this basis, we present theoretical predictions covering the sequence o f H-burning stars as observed in Galactic globulars from the faint end of t he main sequence up to, and beyond, the cluster turn-off. The role played b y the new model atmospheres is discussed, showing that present models appea r in excellent agreement with models by Baraffe et al. as computed on a qui te similar physical basis. One finds that the theoretical mass-luminosity r elations based on this updated set of models are in good agreement with the empirical data provided by Henry & McCarthy. Comparison with HST observati on discloses that the location on the colour-magnitude diagram of the lower main sequence in Galactic globular clusters appears again in good agreemen t with the predicted sensitive dependence of these sequences on the cluster metallicity.