ram pressure (see equations 9-11 in Kashi & Soker 2007a). Following the model for the post shocked primary wind which had been presented in Kashi & Soker 2007a, we will use the quantity $$\label{eq:fm}
f_m =
 \begin{cases}
v_{\rm wind1} \sin^2\psi                       & \qquad  v_{\rm wind1} \sin^2\psi < \left(\frac{3}{\eta_B \sin^2\psi}\right)^{1/2}
    \\
\left(\frac{3}{\eta_B \sin^2\psi}\right)^{1/2} & \qquad  v_{\rm wind1} \sin^2\psi < \left(\frac{3}{\eta_B \sin^2\psi}\right)^{1/2}
 \end{cases}$$ where $\psi$ is the angle between the slow wind velocity and the primary wind shockwave, $v_{\rm wind1}$ is the relative speed between the secondary and the primary wind, given in equation (\[eq:vwind1\]) below, and $\eta_B=0.002$ is a parameter (Kashi & Soker 2007a).

The value of $\eta_B=0.002$ implies that the magnetic field has a negligible role before the shock, but not after. The column density is $$n_H = \frac{0.43f_m \dot M_1}{4 \pi r_{1s}^2 v_{\rm wind1} \mu m_H } .
\label{eq:nH}$$ The compression factor together with a few more assumptions allow us to calculate the velocity of the post shock primary wind out from the shock region, and the width of the conical shock, $d_p$ (see equation 12 in Kashi & Soker 2007a). From the width we can calculate the values of $l_{out}$ and $l_{in}$, defined in Fig. \[fig:NHgeo\].

The source of 