Upper panel: Kippenhahn diagram of our 2 M_⊙[Fe/H] = −0.5 during the first dredge-up and core He burning phases; the green and blue dotted lines delineate the region of maximum nuclear energy production by H- and He-burning, respectively. Middle panel: evolution of the central neutron density N_n, central ¹³C mass fraction (×10⁶) and neutron exposure τ. Lower panel: evolution of the central temperature T_c and density ρ_c.