Evolution of the mass of the convective core as a function of the relative time spent on the main sequence (0 is ZAMS and 1 is TAMS) for models at Z_init = 0.040 (upper panel), 0.014 (middle panel), and 0.006 (lower panel). The models are for stellar masses of, from top to bottom, 1.26, 1.24, 1.22, and 1.20 M_⊙ (as labeled on the continuous lines in all panels), 1.18 M_⊙ (long dashed lines in the middle and lower panels), and 1.10 M_⊙ (short dashed line in the lower panel).