Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: B-type Supergiants in the SMC: Chemical compositions and comparison of
  static and unified models   High-resolution UCLES/AAT spectra are presented for nine B-type supergiants
in the SMC, chosen on the basis that they may show varying amounts of
nuclear-synthetically processed material mixed to their surface. These spectra
have been analysed using a new grid of approximately 12 000 non-LTE line
blanketed {\sc tlusty} model atmospheres to estimate atmospheric parameters and
chemical composition. The abundance estimates for O, Mg and Si are in excellent
agreement with those deduced from other studies, whilst the low estimate for C
may reflect the use of the \ion{C}{ii} doublet at 4267\AA. The N estimates are
approximately an order of magnitude greater than those found in unevolved
B-type stars or \ion{H}{ii} regions but are consistent with the other estimates
in AB-type supergiants. These results have been combined with results from a
unified model atmosphere analysis of UVES/VLT spectra of B-type supergiants
(Trundle et al. \cite{Tru04}) to discuss the evolutionary status of these
objects. For two stars that are in common with those discussed by Trundle et
al., we have undertaken a careful comparison in order to try to understand the
relative importance of the different uncertainties present in such analyses,
including observational errors and the use of static or unified models. We find
that even for these relatively luminous supergiants, {\sc tlusty} models yield
atmospheric parameters and chemical compositions similar to those deduced from
the unified code {\sc fastwind}.

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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-ex
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg
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The categories of this paper are: math-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-th
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The categories of this paper are: chem-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: hep-lat
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The categories of this paper are: quant-ph