Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: C2D Spitzer-IRS spectra of disks around T Tauri stars V. Spectral
  decomposition   (Abridged) Dust particles evolve in size and lattice structure in
protoplanetary disks, due to coagulation, fragmentation and crystallization,
and are radially and vertically mixed in disks. This paper aims at determining
the mineralogical composition and size distribution of the dust grains in disks
around 58 T Tauri stars observed with Spitzer/IRS. We present a spectral
decomposition model that reproduces the IRS spectra over the full spectral
range. The model assumes two dust populations: a warm component responsible for
the 10\mu m emission arising from the disk inner regions and a colder component
responsible for the 20-30\mu m emission, arising from more distant regions. We
show evidence for a significant size distribution flattening compared to the
typical MRN distribution, providing an explanation for the usual boxy 10\mu m
feature profile generally observed. We reexamine the crystallinity paradox,
observationally identified by Olofsson et al. (2009), and we find a
simultaneous enrichment of the crystallinity in both the warm and cold regions,
while grain sizes in both components are uncorrelated. Our modeling results do
not show evidence for any correlations between the crystallinity and either the
star spectral type, or the X-ray luminosity (for a subset of the sample). The
size distribution flattening may suggests that grain coagulation is a slightly
more effective process than fragmentation in disk atmospheres, and that this
imbalance may last over most of the T Tauri phase. This result may also point
toward small grain depletion via strong stellar winds or radiation pressure in
the upper layers of disk. The non negligible cold crystallinity fractions
suggests efficient radial mixing processes in order to distribute crystalline
grains at large distances from the central object, along with possible nebular
shocks in outer regions of disks that can thermally anneal amorphous grains.

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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
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The categories of this paper are: econ
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The categories of this paper are: nlin
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The categories of this paper are: physics
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The categories of this paper are: acc-phys
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: gr-qc