A spectroscopic search for luminous companions to WC9-type Wolf-Rayet stars
making circumstellar dust reveals the presence of absorption lines attribu
table to companions in the blue spectra of WR 69 (HD 136488) and WR 104 (Ve
2-45), Comparison of spectra of WR 104 observed in 1995 and 1997 showed the
absorption lines to be more conspicuous in the latter observation and the
emission lines weaker, suggesting a selective eclipse of the WC9 star simil
ar to that observed by Crowther in 1996, The WC9 emission-line spectra are
shown to be less uniform than previously thought, showing a significant ran
ge of O II line strengths. The only two WC9 stars in the observed sample th
at do not make circumstellar dust, WR 81 (He3-1316) and WR 92 (HD 157451),
are found to have anomalously weak O II and strong Heir lines. We suggest t
hat these spectroscopic differences may reflect a compositional difference
that plays a role in determining which of the WC9 stars make dust.