Fig. 15.—
Mixing-ratio profiles for several species of interest (as labeled) in our kinetics/transport models for GJ 436b, for an assumed atmospheric metallicity of 300× solar in carbon and nitrogen, with the oxygen elemental abundance defined through an assumed C/O ratio of 0.6. The eddy diffusion coefficients are taken to be Kzz = 107 cm2 s−1 at P ≥ 10−4 bar, with Kzz increasing as the inverse square root of the pressure at P < 10−4 bar. The thermal profile is taken from Fig. 4 of Madhusudhan & Seager (2011), but we have shifted the entire profile upwards uniformly in an attempt to account for the higher-altitude photosphere with higher metallicities (see text). A color version of this figure is available in the online journal.