Top left and third row, left: visual extinction maps from Herschel data (Jason Kirk, priv. comm.) of the TMC 1-C and TMC 1-CP cores, respectively, with the areas mapped in the transitions presented in Table 1. Contour lines show levels of extinction of 6, 10, 15, and 20 mag. The blue and red spectra show the observed molecular lines in TMC 1-C and TMC 1-CP, respectively. The solid lines show synthetic spectra created with the model parameters present in Table 3.