Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Weak-line T Tauri Star Disks I. Initial Spitzer Results from the Cores
  to Disks Legacy Project   Using the Spitzer Space Telescope, we have observed 90 weak-line and
classical T Tauri stars in the vicinity of the Ophiuchus, Lupus, Chamaeleon,
and Taurus star-forming regions as part of the Cores to Disks (c2d) Spitzer
Legacy project. In addition to the Spitzer data, we have obtained
contemporaneous optical photometry to assist in constructing spectral energy
distributions. These objects were specifically chosen as solar-type young stars
with low levels of H alpha emission, strong X-ray emission, and lithium
absorption i.e. weak-line T Tauri stars, most of which were undetected in the
mid-to-far IR by the IRAS survey. Weak-line T Tauri stars are potentially
extremely important objects in determining the timescale over which disk
evolution may take place. Our objective is to determine whether these young
stars are diskless or have remnant disks which are below the detection
threshold of previous infrared missions. We find that only 5/83 weak-line T
Tauri stars have detectable excess emission between 3.6 and 70 micron which
would indicate the presence of dust from the inner few tenths of an AU out to
the planet-forming regions a few tens of AU from the star. Of these sources,
two have small excesses at 24 microns consistent with optically thin disks; the
others have optically thick disks already detected by previous IR surveys. All
of the seven classical T Tauri stars show excess emission at 24 and 70 micron,
although their properties vary at the shorter wavelengths. Our initial results
show that disks are rare among young stars selected for their weak H alpha
emission.

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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: math
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: nucl-ex
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The categories of this paper are: mtrl-th
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The categories of this paper are: funct-an
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: cs
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The categories of this paper are: nucl-th