1998A&A...330..285H -
Astronomy and Astrophysics, volume 330, 285-305 (1998/2-1)
Quantitative UV spectroscopy of early O stars in the Magellanic Clouds. The determination of the stellar metallicities.
HASER S.M., PAULDRACH A.W.A., LENNON D.J., KUDRITZKI R.-P., LENNON M., PULS J. and VOELS S.A.
Abstract (from CDS):
UV spectra of 4 O-stars in the Magellanic Clouds obtained with the Faint Object Spectrograph of the Hubble Space Telescope are analyzed with respect to metallicity. With the stellar parameters Teff,logg, R*, and the mass loss rates {dot}(M) known from optical analyses, the metal abundances including iron group elements are derived in two steps. First, hydrodynamic radiation driven wind NLTE models with metallicity as a free parameter are constructed to fit the observed wind momentum rate and thus, yield a dynamical metallicity. Then, synthetic spectra are computed for different metal abundances and compared to the observed spectra to obtain a spectroscopic metallicity. In general, the results obtained from both methods agree. For the two stars in the Small Magellanic Cloud (NGC346#3, O3III(f*) and AV243, O6V) metallicities of logz/z☉=-0.7 and -0.8, respectively, are found. The O3 star shows evidence for CNO-cycled matter in its atmosphere. The metallicity of the two stars in the Large Cloud (Sk-68 137, O3III(f*) and Sk-67 166, O4If+) are constrained to logz/z☉=-0.3 and -0.1. Because of saturation effects in the cores of the pseudophotospheric metal lines the determination of the LMC metallicity is less reliable.
Abstract Copyright:
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Journal keyword(s):
stars: early type - mass loss - line: profiles - stars: abundances - Magellanic Clouds
CDS comments:
NGC 346 3 = Cl* NGC 346 WB 3
Simbad objects:
8
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