Forbidden Emission Lines in Massive Colliding Wind Binaries
East Tennessee State University
I will discuss the possibility of probing the geometry of massive star colliding winds and their binary orbits using forbidden emission line shapes. The principal systems of consideration are binaries involving a Wolf-Rayet star and an OB companion. Since forbidden line emission forms at large radius from the Wolf-Rayet component, the wind interaction can be treated in large part as an archimedean spiral, although this will depend on the binary separation in relation to the critical radius for any particular line. The motivation is that a spherical wind should produce a flat-topped (or box-shaped) emission line profile. The wind collision leads to deviations of the profile shape from a flat-top, which is seen in ISO data of gamma Vel and WR 147. The key results are that (a) there are useful trends between profile shape and the viewing perspective as well as the colliding wind geometry, such as the bow shock opening angle and (b) multiple forbidden lines from the same system probe different regions of the colliding wind geometry so that coarse mapping of that geometry is possible, in principle. Applications to gamma Vel and WR 147 are presented.
Date: Thursday, 11 December 2008 Time: 12:30 Where: Université de Montréal Pavillon Roger-Gaudry, Local D-460 Contact: Nicole St-Louis