Structure and evolution of low-mass stars

We present extensive calculations of the structure and the evolution of low-mass stars in the range 0.07-0.8 M., for metallicities -2.0 less than or equal to [M/H] less than or equal to 0.0. These calculations are based on the most recent description of the microphysics characteristic of these dense and cool objects and on the latest generation of grainless non-grey atmosphere models. We examine the evolution of the different mechanical and thermal properties of these objects as a function of mass and metallicity. We also demonstrate the inaccuracy of grey models and T(tau) relationships under these conditions. We provide detailed cables of the mass-radius-luminosity-effective temperature relations for various ages and metallicities, aimed at calibrating existing or future observations of low-mass stars and massive brown dwarfs. We derive new hydrogen-burning minimum masses, within the afore-mentioned metallicity range. These minimum masses are found to be smaller than previous estimates, a direct consequence of non-grey effects. At last, we examine the evolution of the abundance of light elements, Li, Be and B, as a function of age, mass and metallicity.