Kippenhahn diagram of the inner 6 M_⊙ core structure of models with the same core mass and different core carbon abundance at core C ignition. Colors indicate the dimensionless electron degeneracy parameter η = μ/k_BT (electrons are partially degenerate for η ≈ 0 and very degenerate for η ≫ 0). Convective zones are highlighted by the hatched regions and the dotted vertical lines indicate, from left to right, the moments when ¹²C, ²⁰Ne, ¹⁶O, and ²⁸Si are depleted at the center (central abundance lower than 10⁻⁴). The gray full and dashed lines indicate the classical (M_Ch, 0) and effective (M_Ch) Chandrasekhar mass, respectively. Electron degeneracy during core carbon burning increases for models with lower central carbon abundances.