Distribution of ⁴⁰Ca in the interior of all stellar models as a function of their mass (top: single stellar models; bottom: binary-stripped stars). All models, represented as bars, are shown as a function of their initial mass. The length of each bar gives the mass of this model at the onset of core collapse. The binary-stripped star model with an initial mass of 19 M_⊙ is not shown because it did not reach core collapse due to numerical issues.