Migratory Outbursting Quasi-Hilda Object 282P/(323137) 2003 BM80* **

Abstract

We report that object 282P/(323137) 2003 BM80 is undergoing a sustained activity outburst, lasting over 15 months thus far. These findings stem in part from our NASA Partner Citizen Science project Active Asteroids (http://activeasteroids.net), which we introduce here. We acquired new observations of 282P via our observing campaign (Vatican Advanced Technology Telescope (VATT), Lowell Discovery Telescope (LDT), and the Gemini South telescope), confirming 282P was active on UT 2022 June 7, some 15 months after 2021 March images showed activity in the 2021–2022 epoch. We classify 282P as a member of the quasi-Hilda objects (QHOs), a group of dynamically unstable objects found in an orbital region similar to, but distinct in their dynamical characteristics to, the Hilda asteroids (objects in 3:2 resonance with Jupiter). Our dynamical simulations show 282P has undergone at least five close encounters with Jupiter and one with Saturn over the last 180 yr. 282P was most likely a Centaur or Jupiter-family comet (JFC) 250 yr ago. In 350 yr, following some 15 strong Jovian interactions, 282P will most likely migrate to become a JFC or, less likely, an outer main-belt asteroid orbit. These migrations highlight a dynamical pathway connecting Centaurs and JFCs with quasi-Hildas and, potentially, active asteroids. Synthesizing these results with our thermodynamical modeling and new activity observations, we find volatile sublimation is the primary activity mechanism. Observations of a quiescent 282P, which we anticipate will be possible in 2023, will help confirm our hypothesis by measuring a rotation period and ascertaining the spectral type.

Recurring Activity Discovered on Quasi-Hilda 2009 DQ118

“…In addition to its residence on the tenuous T J = 3 asteroidcomet boundary, 2009 DQ 118 exhibits many dynamical similarities to other active quasi-Hildas, such as 282P (Chandler et al 2022). At a ≈ 3.6 au, 2009 DQ 118 sits slightly outside of the quasi-Hilda semimajor axis range of ∼3.7 au < a < ∼4.2 au given by Toth (2006), placing it closer to the Cybele asteroid group than to the Hildas.…”

“…Thermal fracture is primarily applicable for near-Earth asteroids that experience large temperature gradients (several hundred degrees) over their orbits (see Chandler et al 2022;Jewitt & Hsieh 2022 and references therein). Additionally, observations of objects that are likely candidates for thermal fracture-driven activity have found either a lack of evidence for activity for 2005 UD (Kueny et al 2023), or, for (3200) Phaethon, that the observed activity is likely associated with gas emission rather than thermal fracture (Hui 2023); hence, this is an unlikely mechanism to explain the activity seen on 2009 DQ 118 .…”

“…The quasi-Hildas have short dynamical lifetimes, and some of them likely migrated to their current orbits from the outer solar system through interactions with the giant planets (Gil-Hutton & García-Migani 2016). Additionally, relatively few quasi-Hildas (<15) have been found to exhibit comet-like activity (Chandler et al 2022) out of the ∼300 identified so far (Gil-Hutton & García-Migani 2016), with activity on many of these objects being discovered in recent years, for example, 2008 GO 98 (García-Migani & Gil-Hutton 2018), P/2010 H2 (Jewitt & Kim 2020), 282P (Chandler et al 2022), and 2018 CZ 16 (Trujillo et al 2023). Shoemaker-Levy 9, a comet known for its well-observed impact with Jupiter, was also likely a quasi-Hilda (Ohtsuka et al 2008).…”

The Active Asteroids Citizen Science Program: Overview and First Results

“…This dynamical class shares a name with the Hilda asteroids, a small body population bound in stable 3:2 interior mean motion resonance (MMR) with Jupiter, and span a region from the outer asteroid belt to the Jupiter Trojans (Szabó et al 2020). However, quasi-Hildas are not in true resonance with Jupiter, though their orbits are reminiscent of the Hildas when observed in the Jupiter corotating reference frame (Chandler et al 2022), as discussed later in Section 6. Consequently, these objects are challenging to identify, with dynamical modeling requisite to confirm a quasi-Hilda orbit confidently.…”

“…We initially created the Hunting for Activity in Repositories with Vetting-Enhanced Search Techniques (HARVEST) pipeline for our proof-ofconcept work, Searching Asteroids For Activity Revealing Indicators (SAFARI; Chandler et al 2018). Since then, we have substantially improved upon and optimized HARVEST (Chandler et al 2019(Chandler et al , 2020(Chandler et al , 2021(Chandler et al , 2022Chandler 2022), so we provide here a comprehensive description of the complete system.…”