Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Near-infrared emission from sublimating dust in collisionally active
  debris disks   Hot exozodiacal dust is thought to be responsible for excess near-infrared
(NIR) emission emanating from the innermost parts of some debris disks. The
origin of this dust, however, is still a matter of debate. We test whether hot
exozodiacal dust can be supplied from an exterior parent belt by
Poynting-Robertson (P-R) drag, paying special attention to the pile-up of dust
that occurs due to the interplay of P-R drag and dust sublimation.
Specifically, we investigate whether pile-ups still occur when collisions are
taken into account, and if they can explain the observed NIR excess. We compute
the steady-state distribution of dust in the inner disk by solving the
continuity equation. First, we derive an analytical solution under a number of
simplifying assumptions. Second, we develop a numerical debris disk model that
for the first time treats the complex interaction of collisions, P-R drag, and
sublimation in a self-consistent way. From the resulting dust distributions we
generate thermal emission spectra and compare these to observed excess NIR
fluxes. We confirm that P-R drag always supplies a small amount of dust to the
sublimation zone, but find that a fully consistent treatment yields a maximum
amount of dust that is about 7 times lower than that given by analytical
estimates. The NIR excess due this material is much smaller (<10^-3 for A-type
stars with parent belts at >1 AU) than the values derived from interferometric
observations (~10^-2). Pile-up of dust still occurs when collisions are
considered, but its effect on the NIR flux is insignificant. Finally, the
cross-section in the innermost regions is clearly dominated by barely bound
grains.

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The categories of this paper are: physics
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The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
10
The categories of this paper are: q-bio
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
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The categories of this paper are: math
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol