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D. C. Stephens, K. S. Noll (Space Telescope Science Institute), W. M. Grundy (Lowell Observatory)
Vital to understanding the origin and nature of transneptunian objects (TNOs) is the discovery and characterization of binary TNO systems. Only able to form in dense environments, the survival of these systems places strong constraints on the initial conditions and evolution of the Kuiper Belt over time. However, the limited number of known binary systems (currently 14) makes it nearly impossible to draw any significant conclusions about the formation and evolution of the Kuiper Belt. A much larger, diverse sample of binaries among each dynamical group is necessary before fundamental questions about the origin and early evolution of the Kuiper Belt can be answered.
Thus we have designed a second generation search of HST photometry to identify several new binary systems. This search is an extension of our previous work in which we observed 122 unique TNOs using the WFPC2 and NICMOS instruments. In both cases, the sensitivity to binaries was comparable with limits on the separation of 0.15 arcseconds or greater, and magnitude differences of less than 1 mag. From this first generation search, we discovered 6 binary objects, yielding a discovery rate of 5%.
Our second-generation search using PSF fitting has identified a small number of new binary systems that are just below the resolution of the NICMOS and WF cameras. These results suggest that a significantly higher fraction of binary TNOs may lie just at the limit of HST resolution, and that the number of binary systems is increasing with decreasing separation. At this meeting we will present the results of this research, along with details on the binary PSF fitting routine, and our plans to follow-up these discoveries with high resolution imaging using the HRC camera on ACS.
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Bulletin of the American Astronomical Society, 36 #4
© 2004. The American Astronomical Soceity.