FOR RELEASE: January 19, 2006

PHOTO NO.: STScI-PRC06-05

DUSTY PLANETARY DISKS AROUND TWO NEARBY STARS RESEMBLE OUR KUIPER BELT

These two bright debris disks of ice and dust appear to be the
equivalent of our own solar system's Kuiper Belt, a ring of icy rocks
outside the orbit of Neptune and the source of short-period comets. The
disks encircle the types of stars around which there could be habitable
zones and planets for life to develop. The disks seem to have a central
area cleared of debris, perhaps by planets.

For images and more information about this research on the Web, visit:

http://hubblesite.org/news/2006/05

http://www.berkeley.edu/news/media/releases/2006/01/19_kuiper.shtml

Astrophysics, abstract
astro-ph/0511219

From: Mark Wyatt [view email]

Date: Tue, 8 Nov 2005 13:12:08 GMT (261kb)

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

Authors: M. C. Wyatt

Comments: 12 pages, accepted by ApJ

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