Final core masses for different initial metallicity (left), and overshoot factors (right). Models that experience thermal runaway develop a core between M_c ≃ 1.35 − 1.37 M_⊙ (thin, hatched region) due to helium shell burning. Missing data points correspond to models which retain an envelope of more than ∼0.1 M_⊙ at the end of the simulation run, hence their final core mass could not be accurately estimated. Nonfilled data points correspond to the interpolated core mass based on a fitting function (dashed curves) that was applied to models without overshooting and assumes a form: a(x − b)³ + c. These coefficients are (a, b, c) = (0.201 ± 0.007, 2.224 ± 0.036, 1.352 ± 0.026), (0.201 ± 0.006, 2.252 ± 0.022, 1.364 ± 0.015), and (0.196 ± 0.006, 2.336 ± 0.018, 1.356 ± 0.009) for models with Z = 10⁻⁴, Z = 10⁻³, and Z = 0.02 respectively. Green, blue, and red colored regions represent 3σ confidence levels based on the standard deviation error estimates of the fitting parameters.