Spectral energy distributions starless cores (upper) and protostellar envelopes (lower). Shown are the background-subtracted fluxes for the isolated models (left) and their embedded variants (right). Subscripts of the curve labels (F₃₀ to F_0.03) indicate the model mass (in M_⊙). For protostellar envelopes of the same mass, the SEDs with higher fluxes correspond to higher accretion luminosities L_⋆ (0.03, 0.1, 0.3, 1, 3, 10, 30 L_⊙). Dashed lines indicate the fluxes of the ISRF that were integrated over the projected area of either the isolated models or the embedding clouds.