Program: GN-2011B-Q-24

B[e]sg are B-type supergiants, surrounded by non-spherical envelopes from which strong line emission originates. Their strong infrared excess emission suggested that these stars were surrounded by geometrically thick, high-density dusty disks. Rapid rotation discovered in some of these stars supported the idea of rotationally-triggered disk-formation. Hence the material is revolving around the star on (quasi-)Keplerian orbits. However, any attempt to theoretically generate a Keplerian disk around a rotating B[e]sg has failed. On the other hand, the new wind solutions recently found by Cure and collaborators give a natural explanation for the observed density enhancements in the equatorial wind regions. They result in radial velocity distributions delivering line-of-sight velocities different from those of a Keplerian rotating disk. Consequently, detailed kinematical studies of the equatorial disk/wind material give direct proof of the slow-wind scenario. CO molecules are the most capable tracer of the kinematics within cool and dense regions: their first-overtone bandhead structure (2.3 microns) is sensitive to the motion of the CO gas. Thus, we plan to observe the bandheads of galactic B[e]sg with confirmed CO band emission. R=18000 provided by GNIRS, is sufficient to properly resolve the kinematically broadened bandhead structures and to unambiguously test the slow-wind scenario.