Paper: astro-ph/0511219
Date: Tue, 8 Nov 2005 13:12:08 GMT (261kb)

Title: Dust in Resonant Extrasolar Kuiper Belts - Grain Size and Wavelength
Dependence of Disk Structure

Authors: M. C. Wyatt

Comments: 12 pages, accepted by ApJ
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This paper considers the distribution of dust which originates in the
break-up of planetesimals that are trapped in resonance with a planet. There
are three grain populations with different spatial distributions: (I) large
grains have the clumpy resonant distribution of the planetesimals; (II)
moderate sized grains are no longer in resonance and have an axisymmetric
distribution; (III) small grains are blown out of the system by radiation
pressure and have a distribution which falls off oc 1/r, however these grains
can be further divided into subclasses: (IIIa) grains produced from pop I that
exhibit trailing spiral structure emanating from the clumps; and (IIIb) grains
produced from pop II that have an axisymmetric distribution. Since observations
in different wavebands are sensitive to different sized dust grains,
multi-wavelength imaging can be used to test models for the origin of debris
disk structure. For example, a disk with no blow-out grains would appear clumpy
in the sub-mm, but smooth at mid- to far-IR wavelengths. The wavelength of the
transition is indicative of the mass of the perturbing planet. The size
distribution of Vega's disk is modeled in the light of the recent Spitzer
observations. The origin of the large quantities of pop III grains seen by
Spitzer must be in the destruction of the grains seen in the sub-mm, and so at
high resolution and sensitivity the mid- to far-IR structure of Vega's disk is
predicted to include spiral structure emanating from the sub-mm clumps.

\\ ( http://arXiv.org/abs/astro-ph/0511219 , 261kb)