Title:Be stars - Blue stragglers in the field

Abstract:

Be stars are rapidly rotating B stars. The rapid rotation is the major contributor to forming a mass-loss disk 
around their equator. While some fraction of Be stars was bound to become such already at the ZAMS, 
another part of Be stars certainly underwent spinup (and to a certain degree rejuvenation) when 
mass-transfer occurred during binary evolution. They can be identified by either their dynamical properties as 
runaway stars, or by finding the degenerate left-overs of the former primary when they are still binaries. In 
particular the latter is hard to achieve observationally and there certainly is a large hidden number still to be 
found, so that theoretical predictons and observational estimates of the Be star fraction formed through the 
binary channel still differ significantly.