phase $0.47$ the column density toward this component is $N_H=1.7\pm 0.3 \times 10^{23} \cm^{-2}$, as deduced by XMM-Newton observations (H07). All the $N_H$ observations and their errors as stated by H07 appear in Fig. \[fig:NH\]. Though the compact object dominates the emission, the uncertainty can be somewhat larger due to combination of multiple spectral components in the data. Our confidence in the column density values derived by H07 is based also on their finding that the column density has not varied between phases $0.47$ and $0.923$.

The binary parameters are as in our previous paper (where references are given): The assumed stellar masses are $M_1=120 M_\odot$ and $M_2=30 M_\odot$, the eccentricity is $e=0.9$, and the orbital period is $P=2024 \days$. The stellar winds’ mass loss rates and terminal velocities are $\dot M_1=3 \times 10^{-4} M_\odot \yr^{-1}$, $\dot M_2 =10^{-5} M_\odot \yr^{-1}$, $v_{\rm 1,\infty}=500 \km \s^{-1}$ and $v_{\rm 2,\infty}=3000 \km \s^{-1}$. For these parameters, the half opening angle of the winds collision region (WCR) near apastron is $\phi_a \simeq 60 ^\circ$ (A06). For the inclination angle we take $i = 42^\circ$.

H07 modeled the variable X-ray emission with two components. A hot component that explains all the emission above $5 \keV$, 