Upper panel: central temperature, in million Kelvin, at ZAMS of stellar models at different metallicities as a function of the stellar mass of the models. Each dot represents a computed model. The thick lines indicate the range of stellar masses for each metallicity, where a convective core is present on the ZAMS. The dotted line connects the core temperature at the lowest stellar mass having a convective core, for the different metallicities. Lower panel: same as upper panel, but for the central density.