Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dust temperature and density profiles of AGB and post-AGB stars from
  mid-infrared observations   First mid-infrared images of a sample of AGB and post-AGB carbon stars (V
Hya, IRC +10216, CIT 6 and Roberts 22) obtained at La Silla Observatory (ESO,
Chile) are reported. CIT 6 presents a cometary-like feature clearly seen in the
9.7$\mu$m image, Roberts 22 shows an envelope slightly elongated in the
north-east direction while images of V Hya and IRC+10216 are roughly
spherically symmetric. Using inversion technique, the dust emissivity was
derived from the observed intensity profiles, allowing a determination of the
grain temperature and density distributions inside the envelope for these
stars. Dust masses and mass-loss rates were estimated for V Hya and IRC +10216.
Our results are comparable to those obtained in previous studies if dust grains
have dimensions in the range $\sim$ 0.01 - 0.2 $\mu$m. Color maps suggest the
presence of temperature inhomogeneities in the central regions of the dust
envelopes. In the case of V Hya, an eccentric hot point, which direction
coincides with the jet previously seen in [SII] emission, suggest that we are
observing a material ejected in a previous mass-loss event. Bipolar lobes are
clearly seen in the color maps of Roberts 22 and IRC +10216.

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The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
29
The categories of this paper are: funct-an
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The categories of this paper are: stat
25
The categories of this paper are: patt-sol
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
1
The categories of this paper are: cs
8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
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The categories of this paper are: adap-org
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The categories of this paper are: q-alg
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The categories of this paper are: chem-ph