Observed and model visibilities of Sz 71 CO emission, plotted as real and imaginary parts as a function of the baseline (in kλ). The data from the observations are plotted as black data points with error bars, the model with the lowest χ² is shown as solid red curve, and a random set of converged models from the parameter space investigation are drawn as gray curves (mostly covered by the lowest χ² model). This figure was made with the uvplot Python package (Tazzari 2017).