SIMBAD references

Theoretical evolutionary sequences of low mass and metal poor stars have been compured by adopting the latest tabulations of molecular opacity provided by Kurucz (1991), Neuforge (1993), Alexander & Ferguson (1994). The effects on the location of the theoretical Red Giant Branch due to different assumptions on the chemical composition and on the outer boundary conditions, have been investigated. By comparing theoretical RGBs and observational data (Frogel et al. 1983), an attempt has been made to obtain a calibration of the mixing length suitable for metal poor low mass stars. Due to the inclusion of updated low temperature opacities, one finds that an evident correlation between mixing length and metallicity exists. Therefore, some evidence against the use of the solar calibrated mixing length for non solar like stellar structures, is briefly discusses.