|M.Sc Student||Danny Portman|
|Subject||Interaction of Stellar Winds with Circumstellar Matter|
|Department||Department of Physics||Supervisor||Full Professor Soker Noam|
|Full Thesis text|
We perform three-dimensional gas-dynamical simulations of the interaction of free stellar wind ejected by the primary star in the massive binary system eta Carinae with century-old dense gas clouds located in the equatorial plane of the binary system. We show that the asymmetric morphology of the observed blue and red-shifted velocity components of
the outflow at hundreds of astronomical units (AU) from the center of the binary system eta Carinae can be accounted for from the collision of the free primary stellar wind with the slowly expanding dense equatorial gas. Owing to the very complicated structure of the century-old equatorial ejecta, that is not fully spatially resolved by observations, we limit ourselves to modelling the equatorial dense gas by one or two dense spherical clouds. Because of that we only reproduce the general qualitative properties of the velocity maps, but not the ne details.
The ne details of the velocity maps can be matched by simply structuring the dense ejecta in an appropriate way. The blue and red-shifted components are formed in the post-shock ow of the primary wind, on the
two sides of the equatorial plane, respectively. The fast wind from the secondary star plays no role in our model, as for most of the orbital period in our model the primary star is closer to us. The dense clouds are observed to be closer to us than the binary system is, and so in our model the primary star faces the dense equatorial ejecta for the majority of the orbital period.