The top panel shows the hydrogen volume density (dashed) and the gas/dust temperature (solid) profiles as a function of radial extinction A_V and radius r for L1551-IRS5 for default values of the FUV fluxes (G_isrf = 1, G_cr = 10^-4). The bottom panel depicts the abundance structure of water ice (s - H₂O) and water vapour (H₂O) with respect to total hydrogen as modelled with SWaN after t = 1 Myr. The benchmarking of SWaN showed that the abundance of atomic oxygen is not reliably determined deeper into the cloud, which is why X(O) is not shown beyond A_V ≳ 2 mag. The different regions (A-D) are discussed in more detail in the text. It should be noted that in this and subsequent figures, the edge of the envelope is on the left and the protostar on the right-hand side.