AAS 197, January 2001
Session 8. Circumstellar Matter and Winds
Display, Monday, January 8, 2001, 9:30am-7:00pm, Exhibit Hall

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[8.26] New observations and modeling of dusty debris around nearby stars

J. S. Greaves, I. M. Coulson, G. Moriarty-Schieven, E. I. Robson (Joint Astronomy Centre, Hilo), W. S. Holland, W. R. F. Dent, M. Wyatt (UKATC, Royal Observatory Edinburgh), B. Zuckerman, R. Webb, C. McCarthy (Department of Physics & Astronomy, University of California Los Angeles), W. K. Gear (Department of Physics & Astronomy, University of Wales, Cardiff), D. Walther (Gemini Observatory, Hilo), H. Walker (CCLRC, Rutherford Appleton Laboratory), H. Butner (SMTO, University of Arizona, Tucson)

The discovery of large reservoirs of cold dust around nearby stars has provided strong evidence for the existence of planetary systems other than our own. If no planets exist in such systems then the spatial density and brightness of the dust should increase smoothly with drag forces towards the central star. However, if planets do exist interplanetary dust will interact with these larger bodies whilst spiralling in towards the star, resulting in irregular variations in both density and corresponding brightness distribution. Submillimetre-wave techniques can circumvent the difficulties of the starlight that dominates at optical and near-IR wavelengths by studying the faint thermal emission from cold dust grains.

Submillimetre images have shown dust disks similar in size to the Sun's Kuiper Belt of comets, and have revealed evidence of central cavities in the emission near the star - possibly cleared-out by the formation of planets. Although intriguing, many of these observations lack sufficient spatial resolution to investigate smaller scale structure such as asymmetries and warps - potential signatures of planetary perturbations. However, very recent new data at short submillimetre wavelengths of the nearby main-sequence star Fomalhaut suggests the presence of a "warp" in the observed dust torus. A possible explanation of the asymmetry is that it is caused by a perturbation of a hidden planet, and the data can be modeled with a Saturn-like object in a gap in the torus.

In this paper we present a summary of our current understanding of debris disks from submillimetre wavelength studies. Modeling of the dust structures, asymmetries, dust properties and spatial profiles are also discussed.

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