Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Dust Properties of Two Hot R Coronae Borealis Stars and a Wolf-Rayet
  Central Star of a Planetary Nebula: in Search of a Possible Link   We present new Spitzer/IRS spectra of two hot R Coronae Borealis (RCB) stars,
one in the Galaxy,V348 Sgr, and one lying in the LMC, HV 2671. These two
objects may constitute a link between the RCB stars and the late Wolf-Rayet
([WCL]) class of central stars of planetary nebula (CSPNe) such as CPD -56 8032
that has little or no hydrogen in their atmospheres. HV 2671 and V348 Sgr are
members of a rare subclass that has significantly higher effective temperatures
than most RCB stars, but sharing the traits of hydrogen deficiency and dust
formation that define the cooler RCB stars. The [WC] CSPNe star, CPD -56 8032,
displays evidence for dual-dust chemistry showing both PAHs and crystalline
silicates in its mid-IR spectrum. HV 2671 shows strong PAH emission but shows
no sign of having crystalline silicates. The spectrum of V348 Sgr is very
different from those of CPD -56 8032 and HV 2671. The PAH emission seen
strongly in the other two stars is not present. Instead, the spectrum is
dominated by a broad emission centered at about 8.2 micron. The mid-IR spectrum
of CPD -56 8032 shows emission features that may be associated with C60. The
other two stars do not show evidence for C60. HV 2671 has also been detected by
Herschel/PACS and SPIRE. V348 Sgr and CPD -56 8032 have been detected by
AKARI/FIS. These data were combined with Spitzer, IRAS, 2MASS and other
photometry to produce their spectral energy distributions from the visible to
the far-IR. Monte Carlo radiative transfer modeling was used to study the
circumstellar dust around these stars. HV 2671 and CPD -56 8032 require both a
flared inner disk with warm dust and an extended diffuse envelope with cold
dust to to fit their SEDs. The SED of V348 Sgr can be fit with a much smaller
disk and envelope.

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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-th
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The categories of this paper are: supr-con
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The categories of this paper are: nucl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: physics
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: econ
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The categories of this paper are: atom-ph
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The categories of this paper are: solv-int
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The categories of this paper are: chao-dyn
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The categories of this paper are: comp-gas