Radiation-to-gas pressure boundary
= Radiation-to-gas pressure boundary
For a nondegenerate fully ionized gas, equating $P_{\rm gas}=\rho k_BT/(\mu_{\rm mol}m_u)$ with $P_\gamma=a_{\rm rad}T^4/3$ gives $T^3=3k_B\rho/(a_{\rm rad}\mu_{\rm mol}m_u)$. Radiation dominates at higher <temperature> for fixed density. A degenerate <Electron> gas requires its degeneracy <pressure> instead of extrapolating this ideal-gas formula.