Posterior distribution of the ¹³CO model. R (au) is the peak of the Gaussian surface density distribution; ΔR (au), the FWHM of the Gaussian distribution; T₇₃ (K), the temperature at 73 au; β, the temperature power-law index; μ, the mean molecular weight; M_CO (M_⊕), the CO mass; i (deg), the inclination; PA (deg), the position angle; and M_⋆ (M_⊙), the stellar mass. The marginalised distributions are presented in the diagonal. The best-fitting values and uncertainties for the parameters are taken from the 16th, 50th, and 84th percentiles (vertical dashed lines).