[PPS03-P04] Polarimetric Study of Asteroids in Comet-Like Orbits (ACOs)
We conduct a polarimetric study of three candidates of dormant comet nuclei, (331471) 1984 QY1, (3552) Don Quixote and (944) Hidalgo, by using the 1.6-m Pirka Telescope at the Nayoro observatory (operated by Hokkaido University, Japan). We chose these asteroids in comet-like orbits (ACOs) based on the orbital elements (i.e., the Tisserand parameter with respect to Jupiter TJ < 3). We found that 1984 QY1 has a polarimetric albedo (geometric albedo determined via polarimetry) pV = 0.16±0.06 while both Don Quixote and Hidalgo have Rc-band polarimetric albedo pR < 0.05. Based on the polarimetric result together with a dynamical analysis, we conjectured that 1984 QY1 could be an S-type asteroid transported into the current orbit via 3:1 mean motion resonance with Jupiter. From the previous spectroscopic study, Don Quixote and Hidalgo are classified into D-type taxonomic group, which are typical of comet nuclei. In this presentation, we will introduce our polarimetric observations of ACOs and emphasize that polarimetry is a powerful tool for discriminating the asteroidal and cometary origins.