Spherically symmetric model components are clasified into three groups, the “core” (in blue), the “disk” (in green), and the “envelope” components (in gray), according to their physical parameters. The lower panels show the physical parameters, namely, T_dust, τ₁₀₀, N_H2O, and n_H2, covered by each group of components. Our models for ESO 320-G030 use one component from each group, yielding ≈2.2 × 10⁸ combinations. For each combination, χ² is minimized to give the solid angle subtended by each component.