We have computed new models for the lower main sequence of intermediate metallicity clusters, which are relevant for the interpretation of the luminosity function of the globular cluster M4, recently studied by I. King and collaborator down to the main sequence low end. We are examining the role of non grey model atmospheres on the solar type stars pre-MS, a very hot topic under discussion today. We are constructing models of preMS with boundary conditions from the models of F. Kupka and coworkers for the populationI, including the FST treatment of convection, and with the standard MLT treatment and the NextGen model atmospheres by Allard and Hauschildt. In this work, we are understanding the differences between these two sets of model atmospheres and convection treatment. The turnoff and subgiant stars are not evolved, so a different explanation must be found.
Further work is in progress to deal with the expectations for other trace abundances.
We have published the results of the AGB study, which enabled us to calibrate the mass loss rate in these phases. Massive AGBs are also being monitored at the IR telescope in Campo Imperatore, in the framework of an european collaboration. The collaboration with Monica Tosi is in progress, and is providing us with important clues on the models with and without overshooting. Now an extension is planned to cover M dwarf and T dwarf spectra. Series, in press Click here to return to my Home Page.