β and κ₀ as functions of the effective dust temperature T_dust for the dust re-emission spectrum for cores assuming diffuse dust. The cores are either embedded in spherical or cylindrical filaments. The external pressure p_ext/k outside the filaments is assumed to be 2  ×  10⁴, 10⁵, or 10⁶   K/cm³. The corresponding theoretical values labelled by the considered central extinction A_V of the filaments are shown either as diamonds, triangles, or squares. The values obtained for a given external pressure are fitted with a polynomial function shown as solid black lines.