Evolution of central temperature and central density as a function of evolutionary time. Panel a: evolution of central density as a function of evolutionary time for the 10 M_⊙ stars with Z = 0.014 but with different initial rotational velocities of v_ini = 0 km s⁻¹, 120 km s⁻¹, 350 km s⁻¹. Panel b: evolution of central temperature as a function of the evolutionary time for the 10 M_⊙ stars with Z = 0.0008 but with different initial rotational velocities of v_ini = 0 km s⁻¹, 120 km s⁻¹, 350 km s⁻¹.