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E. D. Skillman, H. Lee (Univ. of Minnesota), K. A. Venn (Macalester College)
New optical spectra of 13 H~II regions in WLM were obtained with the EFOSC2 instrument on the 3.6-m telescope at La Silla. From measurements of the temperature-sensitive [O~III]\lambda 4363~Å\ emission line, we derive a mean oxygen abundance of 12+log(O/H) = 7.83 ±0.06, which corresponds to [O/H] = -0.83~dex, or 15% of the solar value. Our reported nebular oxygen abundance agrees with values published in the literature, and is marginally consistent with the mean stellar magnesium abundance [Mg/H] = -0.62. However, there is still a 0.62~dex discrepancy between the oxygen abundance derived for the A-type supergiant star WLM~15 ([O/H] = -0.21) and the nebular value. There may be a connection between the position of WLM~15, the location of a second H~I peak, and regions of higher internal extinction on the southeast side of the galaxy. E.~D.~S. and H.~L. acknowledge partial support from a NASA LTSARP grant NAG~5--9221 and from the University of Minnesota. K.~A.~V. thanks the National Science Foundation for support through a CAREER award AST~99--84073.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.