Overview of the different parameters explored in the DALI models and their effect on the luminosity of ¹³CO and C¹⁸O. The colors indicate the mass of the model. The arrows indicate in which direction the parameter increases in value (see Table 3). The black outlined circles are the same models for each mass in all panels. The black outlined models have the following parameters: γ = 0.8, ψ = 0.2, h_c = 0.2 rad, R_c = 200 au, i = 10° and L_★ = 10 L_⊙. In Appendix D the same plot is shown, but with γ = 0.4 and γ = 1.5, and with R_c = 5 au, R_c = 10 au, R_c = 30 au, and R_c = 60 au, and for the J = 3−2 transition.