Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Herschel discovery of a new class of cold, faint debris discs   We present Herschel PACS 100 and 160 micron observations of the solar-type
stars alpha Men, HD 88230 and HD 210277, which form part of the FGK stars
sample of the Herschel Open Time Key Programme (OTKP) DUNES (DUst around NEarby
S tars). Our observations show small infrared excesses at 160 micron for all
three stars. HD 210277 also shows a small excess at 100 micron, while the 100
micron fluxes of alpha Men and HD 88230 agree with the stellar photospheric
predictions. We attribute these infrared excesses to a new class of cold, faint
debris discs. alpha Men and HD 88230 are spatially resolved in the PACS 160
micron images, while HD 210277 is point-like at that wavelength. The projected
linear sizes of the extended emission lie in the range from ~ 115 to ~ 250 AU.
The estimated black body temperatures from the 100 and 160 micron fluxes are
$\lesssim$ 22 K, while the fractional luminosity of the cold dust is
Ldust/Lstar ~ 10E-6, close to the luminosity of the Solar-System's Kuiper belt.
These debris discs are the coldest and faintest discs discovered so far around
mature stars and cannot easily be explained by invoking "classical" debris disc
models.

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The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
35
The categories of this paper are: mtrl-th
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The categories of this paper are: stat
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: supr-con
0
The categories of this paper are: hep-ph