Meteor showers from active asteroids and dormant comets in near-Earth space: A review

Small bodies in the solar system are conventionally classified into asteroids and comets. However, it is recently found that a small number of objects can exhibit properties of both asteroids and comets. Some are more consistent with asteroids despite episodic ejections and are labeled as "active asteroids", while some might be aging comets with depleting volatiles. Ejecta produced by active asteroids and/or dormant comets are potentially detectable as meteor showers at the Earth if they are in Earth-crossing orbits, allowing us to retrieve information about the historic activities of these objects. Meteor showers from small bodies with low and/or intermittent activities are usually weak, making shower confirmation and parent association challenging. We show that statistical tests are useful for identifying likely parent-shower pairs. Comprehensive analyses of physical and dynamical properties of meteor showers can lead to deepen understanding on the history of their parents. Meteor outbursts can trace to recent episodic ejections from the parents, and "orphan" showers may point to historic disintegration events. The flourish of NEO and meteor surveys during the past decade has produced a number of high-confidence parent-shower associations, most have not been studied in detail. More work is needed to understand the formation and evolution of these parent-shower pairs.