A rotating disk and a rotating ~100km/s bipolar wind emerging from MWC922

In this presentation, I will report on recent results from our successful and pioneering observational program with ALMA to study emerging ultracompact Hii regions using, as new optimal tracers, mm-wavelength recombination lines (mm-RRLs). I will focuss on our study of the "Red Square Nebula" surrounding the B[e]-type star MWC922. The unprecedented angular resolution (up to 20mas) and exquisite sensititivity of these data unveil for the first time the structure and kinematics of the emerging, compact ionized region at its center. We resolve the spatio-kinematic structure of a nearly edge-on disk rotating around a central mass of ~10-15Msun. We also discovered a ~100km/s bipolar ejection orthogonal to the disk that is rotating as well. This is of utmost importance since it represents the first empirical proof of rotation in a bipolar wind expanding at high velocity (∼100 km/s). The fast bipolar wind is actively launched in regions closer than ~29AU most likely by a disk-mediated mechanism. We have modelled our observations using the radiative transfer code MORELI. This has enabled us to describe with unparalleled detail the physical conditions in the inner layers of MWC 922, which has revealed itself as an ideal laboratory for studying the interplay of disk rotation and jet-launching.