Electron-scattering opacity
= Electron-scattering opacity
{title2=$\kappa_{\rm es}$}
Electron-scattering opacity is approximately independent of density and temperature in a fully ionized nonrelativistic plasma of fixed composition. For hydrogen mass fraction $X$, $\kappa_{\rm es}\simeq0.2(1+X)\,{\rm cm^2\,g^{-1}}$.