Discovery and quantitative spectral analysis of an ofpe/WN9 (WN11) star in the Sculptor spiral galaxy NGC 300

We have discovered an Ofpe/WN9 (WN11 following Smith et al.) star in the Sculptor spiral galaxy NGC 300, the first object of this class found outside the Local Group, during a recent spectroscopic survey of blue supergiant stars obtained at the ESO Very Large Telescope. The light curve over a 5 month period in late 1999 displays a variability at the 0.1 mag level. The intermediate-resolution spectra (3800-7200 Angstrom) show a very close resemblance to the Galactic luminous blue variable (LBV) AG Carinae during minimum. We have performed a detailed non-LTE analysis of the stellar spectrum and have derived a chemical abundance pattern that includes H, He, C, N, O, Al, Si, and Fe, in addition to the stellar and wind parameters. The derived stellar properties and the He and N surface enrichments are consistent with those of other Local Group WN11 stars in the literature, suggesting a similar quiescent or post-LBV evolutionary status.