Evolutionary tracks on the Hertzsprung-Russell diagram (left panel) and time evolution of the mass coordinate of the base of the CZ M_BCZ (right), for models K2 with A₂ = 0 (blue line), K2-MZvar with A₂ = 0.12 (orange line), K2-MZ1′ with f_overshoot = 0.01 and t_acc = 3 Myr (green line), and He12Myr (red line) (see Table 1). The filled circles indicate the times at which accretion ends. The open circle in the left panel indicates the position of the Sun. The gray dashed lines show the evolutionary tracks obtained by Kunitomo et al. (2018, for ξ = 0.5, 0.1, and 0).