Chasing Tails: Active Asteroid, Centaur, and Quasi-Hilda Discovery with Astroinformatics and Citizen Science

The 1950 discovery of activity emanating from asteroid (4015) Wilson-Harrington prompted astronomers to realize comet-like activity is not limited to comets. Since then < 30 active asteroids have been discovered, yet they hold clues about fundamental physical and chemical processes in the solar system. Around half of the activity is attributed to sublimation, highlighting asteroids as a "volatile reservoir" - a dynamical group of minor planets that harbor volatiles. Centaurs, found between the orbits of Jupiter and Neptune, were first recognized in 1977 and represent another reservoir. Active Centaurs are also rare, with < 20 known. Understanding the solar system volatile distribution has broad implications, from informing space exploration programs to illuminating how planetary systems form with volatiles prerequisite to life as we know it. We set out to increase the number of known active objects to enable their study as populations. In this dissertation I present (1) our pipeline that extracts images of known minor planets for presentation to Citizen Scientists, (2) our proof-of-concept demonstrating Dark Energy Camera images are ideal for activity detection (Chandler et al. 2018), (3) how we identified a potential new recurrent activity mechanism (Chandler et al. 2019), (4) a Centaur activity discovery, plus a novel technique to estimate which species are sublimating (Chandler et al. 2020), (5) how our project enabled us to classify an object as a member of the main-belt comets (Chandler et al. 2021), a rare (<10) active asteroid subset known for sublimation-driven activity, (6) the identification of a Quasi-Hilda comet and a dynamical pathway that may explain the presence of some active asteroids (Chandler et al. 2022), and (7) our NASA Partner Citizen Science project Active Asteroids (http://activeasteroids.net), including initial results.