Evolution of various physical parameters of the 15 M_⊙ models. Left panel: evolutionary tracks during the MS phase in the Hertzsprung-Russell diagram of the 15 M_⊙ at Z = 0.014 and with V_ini/V_crit = 0.4. The letters A to G correspond to the models described in Table 1. Center panel: variation in the mass fraction of hydrogen as a function of the Lagrangian mass coordinate when the central mass fraction of hydrogen is 0.35 (X_c = 0.35). Right panel: evolution of the angular velocity vs. the internal mass coordinate at X_c = 0.35 through hydrogen burning.