Massestimates from fitting the 6σ edges of the PV diagrams of CH₃CN (12₄−11₄) shown in Fig. 7 using the method introduced by Seifried et al. (2016) for the model simulations (yellow), ALMA (purple), and NOEMA observations (orange) at 800 pc (left) and 2000 pc (right). The triangles pointing to the left and right correspond to fits to the inner and outer regions, respectively. The diamonds correspond to fits to the entire PV curves. The transparency of the markers correspond to the χ² value of the fit, weighted by the χ² value of the best-fit curve for a given region. The more opaque the marker, the better the fit. The solidand dashed grey curves correspond to the true estimate for the mass of the protostar (10 M_⊙), and the mass of the protostar + disc (18 M_⊙), respectively, corrected by sin² (i) for each inclination i.