Discovery and Quantitative Spectral Analysis of an Ofpe/WN9 (WN11) Star in the Sculptor Spiral Galaxy NGC 300*

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Published 2002 August 26 © 2002. The American Astronomical Society. All rights reserved. Printed in U.S.A.
, , Citation Fabio Bresolin et al 2002 ApJ 577 L107 DOI 10.1086/344241

1538-4357/577/2/L107

Abstract

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 Å) 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.

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Footnotes

  • Based on observations obtained at the ESO Very Large Telescope [65.N-0389(B) and 67.D-0006(A)].

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10.1086/344241