  We address the question of whether the formation of high-mass stars is
similar to or differs from that of solar-mass stars through new molecular line
observations and modeling of the accretion flow around the massive protostar
IRAS20126+4104. We combine new observations of NH3(1,1) and (2,2) made at the
Very Large Array, new observations of CHCN(13-12) made at the Submillimeter
Array, previous VLA observations of NH(3,3), NH(4,4), and previous Plateau de
Bure observations of C34S(2-1), C34S(5-4), and CHCN(12-11) to obtain a data set
of molecular lines covering 15 to 419 K in excitation energy. We compare these
observations against simulated molecular line spectra predicted from a model
for high-mass star formation based on a scaled-up version of the standard
disk-envelope paradigm developed for accretion flows around low-mass stars. We
find that in accord with the standard paradigm, the observations require both a
warm, dense, rapidly-rotating disk and a cold, diffuse infalling envelope. This
study suggests that accretion processes around 10 M stars are similar to those
of solar mass stars.
