Love number k₂ and core masses of two-layer models (squares) and three-layer models (diamonds) of GJ 436b for temperatures of 700 K (cyan) and 1300 K (orange) of the isothermal (1–100 bar) atmosphere. Color coded circles denote models of Jupiter (red), Saturn (yellow), Neptune (blue) and a 20 M_⊕ water planet (black). Three-layer models with the same metal abundance in the outer envelope are connected with dashed (Z₁ = 0), dotted (Z₁ = 0.5) and dash-dotted (Z₁ = 0.7) lines. The grey dashed line marks a highly degenerate area constructed to contain all Z₁ = 0 three-layer models (the position of this line has been shifted compared to Fig. 2 in Nettelmann et al. (2010b) in order to account for the new 1300 K model series).