Mark Jesus Mendoza Magbanua

arXiv2025

Recurrent Cometary Activity Discovered on Quasi-Hilda Jupiter Family Comet 362P/(457175) 2008 GO98

We report the discovery of recurrent activity on quasi-Hilda comet (QHC) 362P/(457175) 2008 GO98. The first activity epoch was discovered during the perihelion passage of 362P. The first activity epoch was discovered during the perihelion in 2016 (Garcia-Migani & Gil-Hutton 2018), so we were motivated to observe it for recurrent cometary activity near its next perihelion passage (UT 2024 July 20). We obtained observations with the Lowell Discovery Telescope (LDT), the Astrophysical Research Consortium (ARC) telescope, and the Vatican Advanced Technology Telescope (VATT) and identified a second activity epoch when 362P had a true anomaly (v) as early as 318.1 deg. We conducted archival searches of numerous repositories and identified images obtained with Canada-France-Hawaii Telescope (CFHT) MegaCam, Dark Energy Camera (DECam), Pan-STARRS 1, SkyMapper, Zwicky Transient Facility (ZTF), and Las Cumbres Observatory Global Telescope (LCOGT) network data. Using these data, we identified activity from a previously unreported timespan, and we did not detect activity when 362P was away from perihelion, specifically 83 deg < v < 318 deg. Detection of activity near perihelion and absence of activity away from perihelion suggest thermally-driven activity and volatile sublimation. Our dynamical simulations suggest 362P is a QHC and it will remain in a combined Jupiter-family comet (JFC) and quasi-Hilda orbit over the next 1 kyr, though it will become increasingly chaotic nearing the end of this timeframe. Our backward simulations suggest 362P may have migrated from the orbit of a Long Period Comet (~53%) or Centaur (~32%), otherwise it remained a JFC (~15%) over the previous 100 kyr. We recommend additional telescope observations from the community as 362P continues outbound from its perihelion on UT 2024 July 20, as well as continued observations for a third activity epoch.

astro-ph.EP↗

arXiv2024

The Active Asteroids Citizen Science Program: Overview and First Results

We present the Citizen Science program Active Asteroids and describe discoveries stemming from our ongoing project. Our NASA Partner program is hosted on the Zooniverse online platform and launched on 2021 August 31, with the goal of engaging the community in the search for active asteroids -- asteroids with comet-like tails or comae. We also set out to identify other unusual active solar system objects, such as active Centaurs, active quasi-Hilda asteroids, and Jupiter-family comets (JFCs). Active objects are rare in large part because they are difficult to identify, so we ask volunteers to assist us in searching for active bodies in our collection of millions of images of known minor planets. We produced these cutout images with our project pipeline that makes use of publicly available Dark Energy Camera (DECam) data. Since the project launch, roughly 8,300 volunteers have scrutinized some 430,000 images to great effect, which we describe in this work. In total we have identified previously unknown activity on 15 asteroids, plus one Centaur, that were thought to be asteroidal (i.e., inactive). Of the asteroids, we classify four as active quasi-Hilda asteroids, seven as JFCs, and four as active asteroids, consisting of one Main-belt comet (MBC) and three MBC candidates. We also include our findings concerning known active objects that our program facilitated, an unanticipated avenue of scientific discovery. These include discovering activity occurring during an orbital epoch for which objects were not known to be active, and the reclassification of objects based on our dynamical analyses.

astro-ph.EP↗