Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Nature of the Dust in the Debris Disk Around HD69830   We have used the infrared mineralogical model derived from the Spitzer IRS
observations of the Deep Impact experiment to study the nature of the dust in
the debris found around the K0V star HD69830 (Beichman et al. 2005). Using a
robust approach to determine the bulk average mineralogical composition of the
dust, we show it to be substantially different from that found for comet
9P/Tempel 1 (Lisse et al. 2006) or C/Hale-Bopp 1995 O1 and comet-dominated YSO
HD100546 (Lisse et al. 2007). Lacking in carbonaceous and ferrous materials but
including small icy grains, the composition of the HD 69830 dust resembles that
of a disrupted P or D-type asteroid. The amount of mass responsible for the
observed emission is the equivalent of a 30 km radius, 2500 kg m-3 sphere,
while the radiative temperature of the dust implies that the bulk of the
observed material is at ~1.0 AU from the central source, coincident with the
2:1 and 5:2 mean motion resonances of the outermost of 3 Neptune-sized planets
detected by Lovis et al. (2006). In our solar system, P and D-type asteroids
are both large and numerous in the outer main belt and near Jupiter (e.g. the
Hildas and Trojans) and have undergone major disruptive events to produce
debris disk-like structures (c.f. the Karin and Veritas families 5-8 Myrs ago).
The short-lived nature of the small and icy dust implies that the disruption
occurred within the last year, or that replenishment due to ongoing collisional
fragmentation is occurring.

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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
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The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph