Planck (top row) and Rosseland (bottom row) mean opacities. Panels a, c: joint dust (Semenov et al. 2003, homogenous IPS) and gas (Malygin et al. 2014) opacities. Panels b, d: pure gas opacity, joint data from Freedman et al. (2008) and Malygin et al. (2014). Data from Freedman et al. (2008) is linearly scaled down in density in log space. The large gas opacity model extrapolates to lower temperatures the values at 650K (the low-temperature cut of data from Malygin et al. 2014); the small gas opacity model extrapolated to lower temperatures the values at 75K (the low-temperature cut of data from Freedman et al. 2008). The numbers on the legend indicate the logarithm base ten of the density in cgs units.