Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: FUSE Observations of Interstellar Gas toward the SMC Star Sk 108   We discuss the interstellar absorption lines found in FUSE spectra of the
Wolf-Rayet binary Sk 108, located in the northeastern part of the main ``bar''
of the Small Magellanic Cloud. The spectra cover the wavelength range 988-1187
Angstroms, at a resolution of about 12,000 and S/N of 20--40. We use detailed
component information from higher resolution near-UV and optical spectra to
model the far-UV lines of similarly distributed species. Both the Galactic and
SMC gas toward Sk 108 seem to be predominantly neutral, though a significant
fraction of the SMC gas is ionized. The column densities of P II, S II, and Ar
I are consistent with essentially solar ratios, relative to N(Zn II), in both
the Galactic and SMC gas; the column density of N I remains somewhat uncertain.
  Molecular hydrogen is present in the Galactic gas, with properties similar to
those found in low mean density Galactic lines of sight and in the Galactic gas
toward several other LMC and SMC stars. We report a tentative detection of H_2
in the SMC gas for J = 1 and 3, with rotational level populations consistent
with an excitation temperature of order 1000 K -- similar to the H_2 found in
diffuse Galactic gas toward zeta Pup. Strong absorption from N III, S III, and
Fe III has revealed a significant ionized component, particularly in the SMC; O
VI is present, but relatively weak, especially in the Galactic gas. The N(C
IV)/N(O VI) ratio varies somewhat within the SMC --- suggesting that several
processes may contribute to the observed high ion abundances.

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The categories of this paper are: nucl-ex
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The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: stat
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an
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The categories of this paper are: cs
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol