The problem of explaining the X-ray emission properties of the massive , close binary WR 20a is discussed .
Located near the cluster core of Westerlund 2 , WR 20a is composed of two nearly identical Wolf- Rayet stars of 82 and 83 solar masses orbiting with a period of only 3.7 days .
Although Chandra observations were taken during the secondary optical eclipse , the X-ray light curve shows no signs of a flux decrement .
In fact , WR 20a appears slightly more X-ray luminous and softer during the optical eclipse , opposite to what has been observed in other binary systems .
To aid in our interpretation of the data , we compare with the results of hydrodynamical simulations using the adaptive mesh refinement code Mezcal that includes radiative cooling and a radiative acceleration force term .
It is shown that the X-ray emission can be successfully explained in models where the wind-wind collision interface in this system occurs while the outflowing material is still being accelerated .
Consequently , WR 20a serves as a critical test-case for how radiatively-driven stellar winds initiate and interact .
Our models not only procure a robust description of current Chandra data , which cover the orbital phases between 0.3 to 0.6 , but provide detailed predictions over the entire orbit .