Gravity (F_gra, red lines) in comparison to radiative forces (F_rad, blue lines) for models M4 (top left), M5 (top right left), M6 (bottom left), and M7 (bottom right). The ratio of forces is defined as ζ = F_rad∕F_gra (purple lines). All cases have a constant dust temperature of T_d = 20 K, an outer radius of R_out = 5 pc and use dust model D2. We note that ζ < 1 everywhere, implying that radiation pressure does not support the cloud against gravitational contraction. The vertical brown line marks the sublimation radius.