Systematic characterization of and search for activity in potentially active asteroids

We report on our long-term observational campaign to characterize and monitor a select sample of 75 dynamically selected dormant comet candidates and six near-Sun asteroids. Both asteroid subpopulations can be considered likely to display comet-like activity. Dormant comets are currently inactive comet nuclei that can still harbor volatiles in subsurface layers, whereas near-Sun asteroids have extremely low perihelion distances and are thus prone to catastrophic disruption. As a result of our 4 yr long observing campaign, we find only dormant comet 3552 Don Quixote to show activity during our program. We furthermore find that (51 ± 10)% of dynamically selected dormant comet candidates in near-Earth space have comet-like physical properties, as well as (56 ± 16)% of dynamically selected dormant comet candidates in other parts of the solar system. All of our near-Sun asteroid sample targets are of nonprimitive nature, suggesting that primitive near-Sun asteroids are more likely to disrupt than nonprimitives. We furthermore find a significant fraction of our near-Sun asteroid sample to display extremely blue V-I color indices, potentially hinting at physical alterations of surface material close to the Sun.