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Multiple Epochs of Activity Discovered on Quasi-Hilda 2009 DQ118

Presentation #102.03 in the session Asteroids: Objects of Interest (Oral Presentation)

Published onOct 23, 2023
Multiple Epochs of Activity Discovered on Quasi-Hilda 2009 DQ118

As a result of our Citizen Science project, Active Asteroids ( — a NASA Partner Program hosted by Zooniverse — we have discovered comet-like activity on minor planet 2009 DQ118. Active Asteroids volunteers identified activity on 2009 DQ118 in publicly-available Dark Energy Camera images (Blanco 4m telescope at Cerro Tololo Inter-American Observatory, Chile) from UT 8-9 March 2016. We subsequently acquired follow-up observations of 2009 DQ118 using the 6.5m Magellan Baade telescope on UT 22 April 2023, and these images also indicate the presence of activity originating from 2009 DQ118. Both of these epochs of activity detection occurred near perihelion for 2009 DQ118. We also performed an archival image search and found hundreds of images of 2009 DQ118 from the interval between these two epochs (when 2009 DQ118 was far from perihelion), none of which showed obvious signs of comet-like activity. The detection of two separate activity epochs near perihelion for 2009 DQ118 indicate that its activity is likely driven by sublimation of volatiles.

In addition to these findings, we examined probable orbital histories and futures for 2009 DQ118, each over a timespan of 10,000 years. We find that 2009 DQ118 likely migrated to its current orbit from either the Centaur or Jupiter Family Comet regions within the last 1,000 years via close encounters with Jupiter. We classify 2009 DQ118 as a quasi-Hilda object, a pseudo-class of small bodies known for their short dynamical lifetimes and their proximity to the Hilda asteroid group.

This work represents one of approximately 20 discoveries resulting from the Active Asteroids project, which has over 8,000 volunteers who have made more than 6 million classifications of images of solar system minor planets in the last two years. This work was funded in part by NASA grants 80NSSC21K0114 and 80NSSC19K0869 and NSF grants 2018258765, 2020303693, and 1950901.

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