Azimuthally averaged profiles for C¹⁸O J = 2 – 1 (left), ¹³CO J = 2 – 1 (middle), and ¹²CO J = 2 – 1 (right) moment zero maps. The modelled curves are the results from two models with different C/O ratios in the disc. The black solid lines were retrieved from the best representative model that uses C/O = 0.457, and the red dashed lines represent simulations with C/O = 1.097. The vertical dashed lines indicate the limits of the dust gap.