  Fast rotation seems to be the major factor to trigger the Be phenomenon.
Surface fast rotation can be favored by initial formation conditions such as
metal abundance. Models of fast rotating atmospheres and evolutionary tracks
are used to determine the stellar fundamental parameters of 120 Be stars
situated in spatially well-separated regions to imply there is between them
some gradient of metallicity. We study the effects of the incidence of this
gradient on the nature of the studied stars as fast rotators.
