Published online by Cambridge University Press: 25 May 2016
There are a number of Wolf-Rayet stars which, based on their emission line profile variations, were proposed to be WR+cc systems (Firmani et al. 1980; Cherepashchuk & Aslanov 1984). However, recent intensive monitoring with different observational techniques, has given rise to alternative explanations for the variability in these WR stars including the presence of a disk, rotating jet-like structures (Vreux et al. 1992), and corotating interaction regions (St-Louis et al. 1995).