... below

Prinja & Massa (1998) suggested a larger observational spread in  $v_{\infty }/v_{\rm esc}$ amongst early B supergiants.

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... turbulence

In CMFGEN this adopted value is technically  $\xi_{\rm min}$, the microturbulence at the base of the wind, which increases with radius to $\xi_{\rm max} = 50$  $\rm {km~s^{-1}}$ at $v_\infty$.

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