The same figures as Figs. 8a and 8b, but with varying accretion history (t_disk, see text) and initial metallicity, Z_ini. The solid lines indicate the cases with Z_ini = Z_⊙(=0.0197) and t_disk = 3 (red line), 10 (blue) and 20 Myr (green) from top to bottom. The dotted and dashed lines represent the cases with Z_ini = 0.03 and 0.01, respectively, and with t_disk = 10 Myr. The other settings are fiducial ones, namely ΔM₀ = 0.03 M_final, ξ = 0.1, the uniform heat distribution and X_D = 28 ppm). In the bottom panel, the cases with Z_ini = 0.01 (blue dashed) and M_final ≤ 1.4 M_⊙ are not plotted because Z_surf = 0. We adopt T_eff at 0.3 Gyr when all stars are in their MS.