AAS 195th Meeting, January 2000
Session 78. Young Stars, Disks and Planets
Display, Friday, January 14, 2000, 9:20am-6:30pm, Grand Hall

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[78.11] Warm Circumstellar Dust in the HD 98800 Quadruple Star System

L. Prato, A.M. Ghez (UCLA), R.K. Pina, C.M. Telesco, R.S. Fisher (University of Florida), P. Wizinowich, O. Lai, D.S. Acton, P. Stomski (W.M. Keck Observatory)

We present diffraction-limited images of the young quadruple star system HD 98800 obtained with the W. M. Keck 10-m telescopes from 1-18 microns using speckle imaging and adaptive optics imaging in the near-infrared, and direct imaging with OSCIR in the mid-infrared. These measurements are the first to resolve the 0.8'' (38 AU) North-South pair at multiple wavelengths through the silicate feature. The emission from HD 98800 A, a single-lined spectroscopic binary, is consistent with a Kurucz model photosphere of temperature 4500 K and luminosity 0.71 Lsun. In contrast, the emission seen in HD 98800 B, a double-lined spectroscopic binary, is fit by a Kurucz model photosphere of 4000 K with L = 0.58 Lsun, and a large mid-infrared to sub-millimeter excess with L = 0.11 Lsun. A black body fit to the excess emission yields a dust temperature of 150 K; there is also a strong 10 micron silicate emission feature. The equilibrium radius of this dust is 2.6 AU, indicating a circum-spectroscopic binary distribution of grains. The very high fractional luminosity of the dust, 0.2 LB, implies a large vertical component to the distribution, possibly a result of dynamical interactions with the central binary.

This research was supported by the NASA Origins of Solar Systems program and the Packard Foundation.

The author(s) of this abstract have provided an email address for comments about the abstract: lprato@astro.ucla.edu

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