Presentation #208.02 in the session MBAs: Physical Characteristics, Part 2.
In 1949 the discovery of an asteroid with a comet tail ushered in an era of increasingly blurred lines between comets and other minor planets classes historically unassociated with activity. These objects, such as active asteroids and active Centaurs (objects found between the orbits of Jupiter and Neptune) and the active Quasi-Hildas that orbit near Jupiter, promise clues to the solar system volatile distribution and even the origins of water on Earth. However, in the last century fewer than 30 active asteroids, 20 active Centaurs, and 15 active Quasi-Hildas have been found. This paucity has proven a hurdle to understanding these enigmatic objects, so we set out to increase the number of known active asteroids and active Centaurs with the help of Citizen Scientists. Citizen Science blends outreach and science, simultaneously engaging the public while accomplishing tasks too complex or numerous for scientists (or machines) to address. For this project we first extract images of known minor planets from public Dark Energy Camera (DECam) data and apply a series of tests to filter out unusable data. We show the resulting vetted images to Citizen Scientists and ask them if they see any activity — such as a tail or coma — coming from the object at the center of the image. On 2021 August 31 we successfully launched the NASA Partner project Active Asteroids (http://activeasteroids.net) on the Zooniverse online Citizen Science platform, and we have been making discoveries ever since.
Here I present highlights from my dissertation, including (1) our pipeline that extracts images of known minor planets from image archives, (2) our proof-of-concept showing DECam data are ideal for identifying active objects, (3) how we revealed an unusual activity mechanism for active asteroid (6478) Gault, (4) our discovery of activity coming from Centaur 2014 OG392, (5) our identification of active asteroid (248370) 2005 QN173 as the ninth known recurrently active Main-belt Comet, a rare active asteroid subset found in the asteroid belt, (6) an introduction to our Citizen Science project, and (7) first results from the project.