Spectral energy distributions of the isothermal models of starless cores (upper) and protostellar envelopes (lower). Shown are the background-subtracted fluxes of the isolated models (left) and of their embedded variants (right). For the cores of increasing masses, T_M = {16.3, 15.0, 13.2, 11.2, 9.25, 7.66, 6.42 K}. For the envelopes of increasing luminosities and masses, T_M = {16.6, 16.8, 17.3, 18.1, 19.5, 21.9, 25.9 K}, T_M = {13.8, 14.1, 14.7, 15.6, 17.1, 19.4, 23.0 K}, T_M = {10.0, 10.4, 11.1, 12.3, 14.1, 16.8, 20.7 K}. See Fig. 4 for more details.