Top: internal density profiles of ice dust aggregates (solid lines) when r _m = 0.1 μm and ρ _c = 0.35 (left) and 0.002 g cm⁻³ (right). The other parameters except for the material density are listed in Table 1. We assume that each ice monomer has a silicate core whose mass equals the mass of an ice mantle, so that ρ _m = 1.45 g cm⁻³. The orange dotted lines show polytropes with a constant polytropic index of 0.5. The dashed lines show the numerically obtained bulk densities. The green dotted lines show the bulk densities obtained analytically from Equation (4). Bottom: internal pressure profiles.