Structure evolution diagrams of the envelope of 2 full pulsation cycles. Colors show the specific released recombination energy ϵ_rec in panel (a), the ionization fractions of hydrogen and helium in panels (b)-(d), the radiative luminosity L_rad in units of the Eddington luminosity L_Edd in panel (e), the opacity κ in panel (f), the specific entropy s in units of Avogadro’s number N_A and the Boltzmann constant k_B in panel (g), and the radial velocity v in units of the sound speed c_s in panel (h). The dashed lines represent lines of constant mass for masses of 12, 11, 10, 9, and 8 M_⊙ from top to bottom. For better visualization, the logmod transformation is used for the specific recombination energy, with logmod(x) = sign(x)log₁₀(|x|+1) (John & Draper 1980).