Mean opacity: comparison to other studies. The Rosseland (top panel) and the Planck (bottom panel) means at a constant gas density of 10^-10g cm^-3. This work – solid line, Helling et al. (2000) – dashed, and Ferguson et al. (2005) – dot-dashed. Data from Ferguson et al. (2005) contain opacity from dust grains. At lower temperatures the Rosseland average from the dust opacity dominates the Rosseland average from the gas opacity, but the Planck mean of the dust is comparable to the Planck mean of the gas.