Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The nature of the compact HII region Sh 2-89 and its stellar content   We present an analysis of the structure and properties of the compact HII
region Sh 2-89, and certain of the young stellar objects (YSOs) within this
regime, using mid-infrared (MIR) mapping derived from the Spitzer Space
Telescope (SST) and visual slit spectroscopy of the inner regions of the
source. We show that the region has a bipolar structure, and contains a variety
of Class I and II YSOs. Much of the MIR emission appears to be dominated by PAH
emission bands, which cause strong increases in flux in the 5.8 and 8.0 microns
photometric channels, whilst the variation of H_alpha, [NII] at 6583 A, [SII]
at 6716+6731 A, and MIR emission profiles confirms the presence of complex
ionisation fronts, and ionisation stratification.

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The categories of this paper are: adap-org
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The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: funct-an
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
1
The categories of this paper are: cs
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The categories of this paper are: econ
37
The categories of this paper are: supr-con
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-ex