Properties of the [Ne II] 12.810 μm emission line for a sample of core-collapse SN models. Top: profile morphology versus wavelength at 350 d after explosion for models s12p0, s15p2, s21p5, he6p0, he8p0, and he12p0. The spectra are scaled to a distance of 10 Mpc and an additional scaling is applied to the He-star explosion models for better visibility. Bottom: evolution of the percentage fraction of the bolometric flux that is radiated in [Ne II] 12.810 μm for our full model sample. The color coding differs between the two panels. A similar plot for [O I] 0.632 μm is shown in the left panel of Fig. A.3. (See Section 5 for discussion.)