A quick note from the quick-notes source, RNAAS (Research Notes of the AAS). This title covers breaking news (relatively) and short pieces regarding the AAS (American Astronomical Society), versus, say, Planetary Science Journal or Astrophysical Journal. In the January RNAAS (vol 9, issue #1):
Chandler, C. O. Sedaghat, N Oldroyd, W. J. et al. AI-enhanced Citizen Science Discovers Cometary Activity on Near-Earth Object (523822) 2012 DG61 art. 3 ada368
Note that there’s a bit of AI hype to this note. In the Active Asteroids program, “citizen scientists” sift through images taken for other reasons. Active asteroids/weak comets are something that (as of now) escapes detection/classification by pattern-recognition algorithms. It takes a human to decisively yea-or-nay a telescope image as containing an active object, and not a smudge on the lens or whatever. Large numbers of amateurs have volunteered for this task, in this project. Currently, computer algorithms are at a level where they can sort likely active objects, or unlikely pixel smudges. These algorithms are, for now, used to help narrow the pipeline: making the job easier for the human volunteers, not doing the job instead of the humans.
Either way, let’s celebrate the end result: the object formerly known as (523822) 2012 DG61 (that is, asteroid DG61) is now known to be active. The body is some sort of dying comet, or perhaps one which was always weak to begin with. And no, the activity is not due to being impacted by a meteor, resulting in a temporary cloud of ejecta. After identifying DG61 as active, investigators dug through archival records. Old images, not recognized at the time, are now seen as showing DG61‘s activity- that is, we precovered it. The odds are against an object being struck by a meteor at multiple times, kicking up multiple, similar dust clouds. This active asteroid now appears to be a legit volatile emitter.