tokens: in our model to reproduce the free–free continuum spectrum flattening near 2 mm and the surface brightness depression at the center in the continuum and mm-RRL maps. We estimate average electron temperatures of T e ~ 8000–11 000 K and densities in the range n e ≈ 10 7 –10 6 cm −3 in the ionized core of MWC 922. A density radial law n e ∝ r −2.7 , and a smooth variation with the latitude (decreasing from the disk outer boundary to the poles) is inferred. The density radial law could be slightly shallower than adopted, as suggested by the H39 α cubes, which show that the emission from this transition arises at slightly larger distances from the center than predicted by our model. We deduce a mass-loss rate of the fast bipolar wind of Ṁ fast ~ few × 10 −6 M ⊙ yr −1 . Assuming that a slow wind is also present at intermediate latitudes (i.e., bridging the ionized surface of the rotating disk and the fast bipolar wind), we obtain a mass-loss rate of Ṁ slow ~ few × 10 −7 M ⊙ yr −1 . The dynamical age of the winds traced by our observations is a few decades at most, with the innermost layers of the fast wind (at ~29–51 au) ejected just ~1.5–2.6 yr ago. The total ionized mass deduced from the free–free continuum emission at millimeter wavelengths is M H II ~ 2 × M ⊙ . The dominant mass component in the close environment of MWC 922 is probably that probed by the ~160 K dust millimeter continuum emission, from which we deduce ~ 8 M ⊙ . In Sect. 5 we discuss the evolutionary status of MWC 922 from different perspectives and provide a number of arguments that favor a post-main sequence stage. We believe that MWC 922 could be a ~15 M ⊙ blue giant (with T eff ~ 20–30 kK and L ⋆ ~ 5.9 × 10 4 L ⊙ ) located at d ~ 3 kpc that has recently left the main sequence (~10 Myr ago) and is probably undergoing a phase of mass exchange with an unseen companion. Appendix A Additional figures The Band 3and Band 6 continuum emission maps of MWC 922 obtained with 15 and 30 mas-resolution, respectively,are shown in Fig. A.1 . We note the X-shaped morphology, reminiscent of that of the near-IR andmid-IR nebulosities around MWC 922 (Sect. 1 ). The predictions from our model, which is described in Sect. 4 and is schematically represented in Fig. 6 , are shown in Fig. A.2 with the same angular resolution. The equatorial plane of the disk is oriented along PA ~ 45°. The velocity-channel maps of the H30 α and H39 α lines towards MWC 922 are presented in Figs. A.3 and A.4 , respectively. In Fig. A.5 a summary of the observational results for the weak non- α mm-RRLs detected in MWC 922 together with our model predictions is offered. In Figs. A.6 and A.7 we summarize the comparison between data and model for the H30 α and H39 α transitions with super-resolution (15 and 30 mas, respectively). For H30 α , we also display the predictions given by a model where rotation has been suppressed in the fast wind to show that when there is no rotation of the fast wind, the peaks of the red- and
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