Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The radial distribution of dust species in young brown dwarf disks   We present a study of the radial distribution of dust species in young brown
dwarf disks. Our work is based on a compositional analysis of the 10 and 20
micron silicate emission features for brown dwarfs in the Taurus-Auriga
star-forming region. A fundamental finding of our work is that brown dwarfs
exhibit stronger signs of dust processing in the cold component of the disk,
compared to the higher mass T Tauri stars in Taurus. For nearly all of our
targets, we find a flat disk structure, which is consistent with the stronger
signs of dust processing observed in these disks. For the case of one brown
dwarf, 2M04230607, we find the forsterite mass fraction to be a factor of ~3
higher in the outer disk compared to the inner disk region. Simple large-scale
radial mixing cannot account for this gradient in the dust chemical
composition, and some local crystalline formation mechanism may be effective in
this disk. The relatively high abundance of crystalline silicates in the outer
cold regions of brown dwarf disks provides an interesting analogy to comets. In
this context, we have discussed the applicability of the various mechanisms
that have been proposed for comets on the formation and the outward transport
of high-temperature material. We also present Chandra X-ray observations for
two Taurus brown dwarfs, 2M04414825 and CFHT-BD-Tau 9. We find 2M04414825,
which has a ~12% crystalline mass fraction, to be more than an order of
magnitude brighter in X-ray than CFHT-BD-Tau 9, which has a ~35% crystalline
mass fraction. Combining with previous X-ray data, we find the inner disk
crystalline mass fractions to be anti-correlated with the X-ray strength.

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The categories of this paper are: eess
2
The categories of this paper are: math
9
The categories of this paper are: nlin
4
The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph