Comparison between the ¹³CO observations (left column) and the three different models (see Fig. 7): warm (W, second column), intermediate (I, third column), and cold (C, fourth column). Emission is simulated with the same visibilities as the observations (25 minutes integration) and for a longer integration time of five hours in a configuration producing a similar beam size. Four representative velocity channels are shown. Top panels: emission at ±2.5 km s⁻¹, which is expected to originate in the disk. Middle panels: blueshifted emission from the disk and far side of the envelope (Δv = −1.58 km s⁻¹), and bottom panels: redshifted emission from the disk and near side of the envelope (Δv = 1.63 km s⁻¹). The color scale is in steps of 3σ, which corresponds to 30.6 (8.8) mJy beam⁻¹ channel⁻¹ for an integration time of 25 minutes (five hours). The black arrow denotes the difference between the warm and intermediate model, which becomes clear for a five hour integration. The position of the continuum peak is marked by a cross; the vertical scale is the same for all velocities, but slightly shifted. The beam is shown in the lower left corner of each panel.