Fast & slow winds from supergiants and Luminous Blue Variables
  We predict quantitative mass-loss rates and terminal wind velocities for
early-type supergiants and luminous blue variables (LBVs) using a dynamical
version of the Monte Carlo radiative transfer method. First, the observed drop
in terminal wind velocity around spectral type B1 is confirmed by the Monte
Carlo method -- at the correct effective temperature of about 21 000 K. This
drop in wind velocity is much steeper than would be expected from the drop in
escape speed for cooler stars. The results may be particularly relevant for
slow winds inferred for some High-Mass X-ray binaries. Second, the strength of
the mass-loss bi-stability jump is found to be significantly larger than
previously assumed. Not only could this make bi-stability braking more
efficient in massive star evolution, but a rotationally-induced version of the
bi-stability mechanism may now be capable of producing the correct density of
outflowing disks around B[e] supergiants, although multi-dimensional modelling
including the disk velocity structure is still needed. For LBVs, we find the
bi-stability jump to become larger at higher metallicities, but perhaps
surprisingly also larger at lower Eddington parameters. This may have
consequences for the role of LBVs in the evolution of massive stars at
different metallicities and Cosmic Epochs. Finally, our predicted low wind
velocities may be important for explaining the slow outflow speeds of supernova
type IIb/IIn progenitors, for which the direct LBV-SN link was first
introduced.
