Multi-wavelength modelling of the circumstellar environment of the massive proto-star AFGL 2591 VLA 3

We have studied the dust density, temperature, and velocity distributions of the archetypal massive young stellar object (MYSO) AFGL 2591. Given its high luminosity (L = 2 x 10(5) L-circle dot) and distance (d = 3.3 kpc), AFGL 2591 has one of the highest root L/d ratio, giving better resolved dust emission than any other MYSO. As such, this paper provides a template on how to use resolved multiwavelength data and radiative transfer to obtain a well-constrained 2D axisymmetric analytic rotating infallmodel. We show for the first time that the resolved dust continuum emission from Herschel 70- mu m observations is extended along the outflow direction, whose origin is explained in part from warm dust in the outflow cavity walls. However, the model can only explain the kinematic features from CH3CN observations with unrealistically low stellar masses (<15M(circle dot)), indicating that additional physical processes may be playing a role in slowing down the envelope rotation. As part of our three-step continuum and line fitting, we have identified model parameters that can be further constrained by specific observations. High-resolution mm visibilities were fitted to obtain the disc mass (6M(circle dot)) and radius (2200 au). A combination of SED and near-infrared observations were used to estimate the luminosity and envelope mass together with the outflow cavity inclination and opening angles.