Top panel: the logarithm of the force multiplier M(t) for the hydrodynamic solution of our O3 V model (red plusses) as a function of the optical depth like parameter t; our fit function Eq. (6) to this data (green line) and the CAK fit function Eq. (19) to this data (blue line). Bottom panel: the force multiplier as a function of radius r for the same star. Note that the CAK force multiplier is smaller than ours for large radii, resulting in a lower predicted ν_∞.