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J.M. Bauer, K.J. Meech (IfA, UH)
There are to date fourteen designated Centaur bodies with orbits that are contained within the heliocentric distances of Jupiter and Neptune. It is thought that their origin is the Edgeworth-Kuiper Belt, the predicted reservoir of the current short period comet population. Yet, only Chiron has been shown to possess a visible coma. We are undertaking an investigation of the physical characteristics of the Centaurs for comparison with our short-period and long-period comet data base. We are targeting the Centaurs near their oppositions in order to determine whether there is evidence for coma and activity on these bodies. Coma is a strong indication of cometary origin. By measuring the coma brightness and color and estimating the particle size range, we can place approximate constraints on the mass outflow, and upper limits on the lifetime of the object. Deep imaging to search for coma requires dark time and many short exposures as the object passes through an uncrowded field on a photometric night. It also requires a moderately large pixel scale which is optimized for good PSF sampling while large enough to collect signal from faint extended sources, as available with observations from Mauna Kea's ground-based observatories. Also, as a consequence of our coma search observations, our data may yield or set limits upon a rotational light curve for each Centaur in a minimum of 2 color bands. We will present preliminary results from observations of 7 Centaurs, taken at the UH 2.2 meter telescope this year.