Radiative and gravitational acceleration at a position R_cavity = 2000 AU (left panel) and R_cavity = 10   000 AU (right panel) above the massive proto-star as a function of the stellar mass M_∗ for three different radiation transport approaches: The label “FLD 1” denotes the FLD approximation with the opacity description of Krumholz et al. (2007). The label “FLD 2” refers to the FLD approximation with the opacities used in Kuiper et al. (2010a, 2011) and in this paper. The label “Ray-Tracing” refers to the RT step as in the hybrid radiation transport scheme.