Physical structure of the best model shown in Fig. 2 and presented in Sect. 6. The orange lines show the profiles of radial velocity (left panel), density (middle panel), and temperature (right panel) in the symmetric model with rotation and the red lines show the modifications introduced in the velocity field in the far-side hemisphere to improve the fit to the line profiles. The tangential (rotational) velocity is not indicated in these plots. The grey line in the temperature panel shows a grey atmosphere temperature profile. The vertical light grey lines mark the transition between the inner and intermediate regions and between the intermediate and outer regions in the model (as shown in Table 1).