The alpha -enhanced Isochrones and Their Impact on the FITS to the Galactic Globular Cluster System

We analyze in detail the effect produced by the enhancement of the α-elements O, Ne, Mg, Si, S, and Ca on the evolutionary properties of low-mass, low-metallicity stars. In particular we address the evolutionary phases which extend from the main sequence up to the H reignition on the asymptotic giant branch. We find that the α-elements other than O cannot be neglected