Sampled 1D marginal posterior cdfs (blue) of model II parameters for Neptune: a) pressure at bottom of atmosphere p_batm; b) atmospheric mass fraction m_atm/M (Eq. (9)); c) temperature-related parameter α; d) number of scale-heights of opaque layers N; e) mean molecular weight μ; f) mass of water m_water; g) mantle radius r_mantle; h) core radius r_core; i) Fe/Si_mantle; j) Mg/Si_mantle. The prior cdfs are plotted in red. Gray areas in b), e), f) represent independent literature estimates (see main text).