Diagnostic diagram of MHD disk-wind launch point and magnetic lever arm, updated from Ferreira et al. (2006) showing specific angular momentum as a function of the total gas velocity. The data points at different altitudes from Fig. A.2 are shown in blue (H¹³CN) and pink (CH₃OH), where a protostellar mass of 0.5 M_⊙ was adopted. The black grid in the background shows the relation between these two quantities predicted when gravitational potential is negligible, for different values of the wind launching radius r0 (solid curves, Eq. (4)) and magnetic lever arm parameter λ_ϕ (dashed curves, Eq. (5)). In contrast to the first version of this diagram, introduced in Ferreira et al. (2006), the x-axis here plots the total gas velocity instead of υ_pol, since the measured υ_ϕ is of the same order as υ_pol. The region with r₀ above the dust disk radius of 23 au is hatched in green.