Comparison of ZAMS relations. ΔM_V represents the magnitude difference between theoretical isochrones and the empirical ZAMS at a given B−V. The effect of the ZAMS on the distance modulus of NGC 2516 is shown on the right‐hand axis. The thick solid, thick dashed, thin solid, and thin dashed lines represent, respectively, the isochrones of Z = 0.019 and log τ = 7.8, Z = 0.02 and log τ = 6.6, Z = 0.008 and log τ = 7.8, and Z = 0.008 and log τ = 6.6 of the Padua group. The thick and thin dotted lines denote the isochrones of Z = 0.02 and log τ = 6.6, and Z = 0.008 and log τ = 6.6 of the Geneva group.