Properties of the Be-type stars in 30 Doradus
  The evolutionary status of Be-type stars remains unclear, with both
single-star and binary pathways having been proposed. Here, VFTS spectroscopy
of 73 Be-type stars, in the spectral-type range, B0--B3, is analysed to
estimate projected rotational velocities, radial velocities and stellar
parameters. They are found to be rotating faster than the corresponding VFTS
B-type sample but simulations imply that their projected rotational velocities
are inconsistent with them all rotating at near critical velocities. The
de-convolution of the projected rotational velocities estimates leads to a mean
rotational velocity estimate of 320-350 km/s, approximately 100 km/s larger
than that for the corresponding B-type sample. There is a dearth of targets
with rotational velocities less than 0.4 of the critical velocity, with a broad
distribution reaching up to critical rotation. Our best estimate for the mean
or median of the rotational velocitiy is 0.68 of the critical velocity.
Rapidly-rotating B-type stars are more numerous than their Be-type
counterparts, whilst the observed frequency of Be-type stars identified as
binary systems is significantly lower than that for normal B-type stars,
consistent with their respective radial-velocity dispersions. The
semi-amplitudes for the Be-type binaries are also smaller. Similar results are
found for a SMC Be-type sample centred on NGC346 with no significant
differences being found between the two samples. These results are compared
with the predictions of single and binary stellar evolutionary models for
Be-type stars. Assuming that a single mechanism dominated the production of
classical Be-type stars, our comparison would favour a binary evolutionary
history.
