ABSTRACT 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 modelling 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 (VLA), new observations of CH3CN(13-12) made at the Submillimeter Array, previous VLA observations of NH3(3,3) and NH3(4,4) and previous Plateau de Bure observations of C34S(2-1), C34S(5-4) and CH3CN(12-11) to obtain a data set of molecular lines covering 15-419 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 disc-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 disc and a cold, diffuse infalling envelope. This paper suggests that accretion processes around 10 Msolar stars are similar to those of solar mass stars.
