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R. S. Fisher, C. M. Telesco, R. K. Pina (U. Florida), R. F. Knacke (School of Science, Penn State Univ. at Erie)
An exploration of the so-called debris, or Vega-type disks associated with main sequence stars will allow us to investigate these systems during that time in which planets may be forming or have already formed. The determination of the composition and structure of these disks will greatly influence our thinking on the process of planet formation. Specifically, once the basic characteristics of this type of disk are known, we can start to answer the crucial question of how these disks relate to our own Solar System, and to planetary systems in general. An investigation of a statistically significant number of these systems gives us the opportunity to determine the relative frequency of occurrence of disks (and possibly companions) around these stars. \\ We report the preliminary results of a mid-IR survey of ~ 25 Vega-Like sources from the list complied by Walker & Wolstencroft (1988, PASP, 100, 1509). Both Northern and Southern hemisphere sources have been imaged at 10 and 20 \micron using OSCIR, the University of Florida imager/spectrometer system, on the CTIO 4 meter and on Keck II. While most of the observed sources are distinctly point-like, our observations show that at least 2 of the sources are extended in one or more of the passbands. Additionally, we present new 18 \micron images of the circumstellar disk around the A0V star HR4796A. These images show detailed structure in the disk, including slight asymmetries in the thermal emission from the dust.
The author(s) of this abstract have provided an email address for comments about the abstract: fisher@astro.ufl.edu