Abundance profiles of the SERIES II 2.7 M_⊙, Z = 0.02; f_OV = 0.0; η = 0.8 stellar model. The left panel refers to the structure when log(ρ_c/g cm⁻³)≃9.0 (shortly before the Urca cooling phase). The right panel shows the final chemical composition of the model after the ignition of neon. This model has reached the critical density for e-captures on ²⁰Ne which leads to the formation of ²⁰O (cyan line).