CMFGEN optical spectra of SNe interacting with their progenitor’s wind at early times for solar (top panel), CNO-processed (middle panel), and He-rich abundances (bottom panel). The models have been convolved with a Gaussian kernel of Δv = 300 km s⁻¹ (resolving power R ≈ 1000), continuum normalised, and shifted for clarity. All the models in this figure have Ṁ = 3 × 10⁻³ M_⊙ yr⁻¹. The labels indicate the adopted values of L₉ (10⁹ L_⊙), and the strongest spectral lines are identified.