A survey of nebulae around galactic Wolf-Rayet stars in the southern sky .3. Survey completion and conclusions

We present the conclusion of a narrow-band optical CCD survey of Wolf-Rayet stars in the southern portion of the Milky Way. In this part of the survey we complete our survey of the southern Galaxy and report the detection of 10 new optical nebulae associated with Wolf-Rayet stars. This brings the final survey total to 40 Wolf-Rayet stars with associated nebulae in 114 southern Galactic fields for a 35% detection rate. Our results suggest that the Galactic environment has little apparent effect on the detection rate of nebulae associated with Wolf-Rayet stars. Indeed, a more important role in the production of nebulae is likely to be played by the evolution of the central star. The survey results also suggest a slightly higher incidence of nebula detection around WN stars over WC stars, although nebulae associated with WC stars are noted as being generally larger and some may have been missed through being larger than the CCD array used. Indeed, the increased rate of nebula detection compared to that of a northern Galactic survey can be accounted for solely through the fact that a larger region of sky around the Wolf-Rayet stars was imaged in our southern survey as compared to the northern survey. Larger nebulae existing around WC as opposed to WN stars are also consistent with the current theory of the evolution of Wolf-Rayet stars from WN to WC.