Comparison between the saturated vapor pressure and the gravitational pressure at 0.1 m and 1 m below the surface of a 100 km-sized planetesimal at different temperatures and for different molecules. The temperature down to 1 m below the surface is assumed to be the same as on the surface. The temperature needs to be about twice as high when considering H₂O molecules than when considering CO₂ molecules inorder for the vapor pressure to win over the gravitational pressure.