Rosseland mean opacities κ_R (left panel) and Planck mean opacities κ_P (right panel) per gram gas as a function of the local radiation temperature T. The label “FLD 1” denotes the opacity description by Krumholz et al. (2007), Eq. (11) therein. The label “FLD 2” denotes the opacities used in Kuiper et al. (2010a, 2011) as well as in this paper; these opacities are computed based on the density-dependent evaporation of dust grains using the low density of the polar cavities.