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Y.R. Fernandez, D.C. Jewitt, S.S. Sheppard (UH-IfA)
A cometary nucleus has several possible end-states, some catastrophic, some not. Measuring the albedo distribution of near-Earth objects in comet-like orbits can provide clues to the number of comets that survive their active lifetime intact to become observationally asteroid-like. By ``comet-like orbit,'' we refer to objects with a Tisserand invariant T in the cometary regime, T<3. We present new radiometric albedos for several inactive objects with T<3, including some retrograde objects. We find that most of these objects are as dark or darker than active cometary nuclei, with geometric albedos around 3%, implying that they are candidate extinct comets. Moreover, the current albedo distribution for inactive objects with T<3 shows that an overwhelming majority are on the dark side, far more than would be estimated by the distribution of the T>3 objects. We place an upper limit of 10% to the fraction of near-Earth and unusual asteroids that are extinct comets. (This work is supported by grants from NSF.)