The standard model of low-mass star formation applied to massive stars:
  multi-wavelength modelling of IRAS 20126+4104
  In order to investigate whether massive stars form similarly to their
low-mass counterparts, we have used the standard envelope plus disc geometry
successfully applied to low-mass protostars to model the near-IR to
sub-millimetre SED and several mid-IR images of the embedded massive star
IRAS20126+4104. We have used a Monte Carlo radiative transfer dust code to
model the continuum absorption, emission and scattering through two azimuthally
symmetric dust geometries, the first consisting of a rotationally flattened
envelope with outflow cavities, and the second which also includes a flared
accretion disc. Our results show that the envelope plus disc model reproduces
the observed SED and images more accurately than the model without a disc,
although the latter model more closely reproduces the morphology of the mid-IR
emission within a radius of 1.1" or ~1800au. We have put forward several
possible causes of this discontinuity, including inner truncation of the disc
due to stellar irradiation, or precession of the outflow cavity. Our best
fitting envelope plus disc model has a disc radius of 9200 au. We find that it
is unlikely that the outer regions of such a disc would be in hydrostatic or
centrifugal equilibrium, however we calculate that the temperatures within the
disc would keep it stable to fragmentation.
