Pointsin the ρ–T plane where the input data have been used to construct the analytical fit. Different symbols correspond to different phase states: crosses for liquid, asterisks for plasma, upright triangles for superionic state, and reverted triangles for ice X. The colors of the symbols represent the accuracy of the fit (for both P and U, i.e., the maximum of the two residuals) according to the palette above the legend. The lines show isentropes of Jupiter (J), according to the models of Leconte & Chabrier (2012) and Nettelmann et al. (2012; the solid and dashed lines, respectively), Saturn (S), according to Leconte & Chabrier (2012), Neptune (N) according to two models of Nettelmann et al. (2013; solid and dashed lines), and a planet with M = 9 M_J (see Baraffe et al. 2008, 2010).