Distribution of Be-XRB orbital parameters in the SR_CS model for Z = 10⁻⁴ (left), Z = 0.0035 (middle), and Z = 0.0142 (right). Each Be-XRB i is weighted by τ_i/M_tot, so that the number for each bin here corresponds to the expected number of binaries in the Be-XRB phase per unit SFR (⁠|$\rm M_\odot \ yr^{-1}$|⁠). In the 2D maps of joint distribution, the solid, dashed, and dotted contours enclose 90 per cent, 50 per cent and 10 per cent of systems from a Gaussian smoothed density field produced by the weighted data. In the marginalized distributions, the solid, dashed, and dotted lines mark the 10, 50, and 90 percentiles.