The entropy per baryon S, and the Bernoulli parameter ε (in units of erg · g⁻¹), of a MESA (A. S. Jermyn et al. 2023) model of a 10 M_⊙ red supergiant envelope, as a function of the mass coordinate. Note that the top panel presents a lower entropy than the expected value of S = 45.0 for a 10 M_⊙ star given by Equation (24), because Equation (24) does not account for the helium present in the envelope of a realistic star.