Slash Stars: Two Types, Two Scenarios?

Of/WN, or as we will call them here, slash / stars were first described by Walborn (1977; 1982a; 1982b) as hot luminous stars that have spectroscopic properties of both O and low-ionization WN spectral classes. Walborn called attention to Sk -67\textdegree 22, an 03If*/WN6-A star that had strong O-type absorption lines, but also a broad emission feature at HeII $\lambda$4686\AA. The / symbol was used to indicate that there was difficulty in assigning either the Of or the WN type unambiguously. He labled other LMC stars as Qfpe/WN9 not only because of a similar ambiguity in the classification but also the presence of narrow nebular emission lines associated with the star. Conti and Garmany (1983) pointed out the similarity of Sk -71\textdegree 34 to Sk -67\textdegree 22. A total of ten stars with Ofpe/WN9 character have now been identified in the LMC (Bohannan and Walborn 1989) : HDE 269927C, 269445, 269582, 269687, 269858, 269227; Sk -66 040, -67 266, -69 297; BE 381.