Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the O/H, Mg/H, Si/H and Fe/H Gas and Dust Abundance Ratios in
  Galactic and Extragalactic H II Regions   We derive the Mg/H ratio in the Orion nebula and in 30 Doradus. We also
derive the O/H and the Fe/O ratios in the extremely metal poor galaxy SBS
0335-052. We estimate the dust depletions of Mg, Si, and Fe in Galactic and
extragalactic H II regions. Based on these depletions we estimate the fraction
of O atoms embedded in dust as a function of the O/H ratio. We find an
increasing depletion of O with increasing O/H. The O depletion increases from
about 0.08 dex, for the metal poorest H II regions known, to about 0.12 dex,
for metal rich H II regions. This depletion has to be considered when comparing
nebular with stellar abundances.

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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: hep-lat
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: stat
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol