A Modern Search for Wolf–Rayet Stars in the Magellanic Clouds. III. A Third Year of Discoveries*

Abstract

For the past three years we have been conducting a survey for Wolf–Rayet (WR) stars in the Large and Small Magellanic Clouds (LMC, SMC). Our previous work resulted in the discovery of a new type of WR star in the LMC, which we are calling WN3/O3. These stars have the emission-line properties of a WN3 star (strong N v , but no N iv ), plus the absorption-line properties of an O3 star (Balmer hydrogen plus Pickering He ii , but no He i ). Yet, these stars are 15 times fainter than an O3 V star, ruling out the possibility that WN3/O3s are WN3+O3 binaries. Here we report the discovery of two more members of this class, bringing the total number of these objects to 10, 6.5% of the LMC’s total WR population. The optical spectra of nine of these WN3/O3s are virtually indistinguishable from each other, but one of the newly found stars is significantly different, showing a lower excitation emission and absorption spectrum (WN4/O4-ish). In addition, we have newly classified three unusual Of-type stars, including one with a strong C iii line, and two rapidly rotating “Oef” stars. We also “rediscovered” a low mass X-ray binary, RX J0513.9-6951, and demonstrate its spectral variability. Finally, we discuss the spectra of 10 low priority WR candidates that turned out to not have He ii emission. These include both a Be star and a B[e] star.