Research of the family associations of active asteroids in the main belt

Abstract

We apply the Hierarchical Clustering method (HCM) and Selective Backward Integration method (BIM) to search for associated families and young families for all main-belt active asteroids (MBAAs) known to date. We find four newly candidate sub-groups of known families, which include the candidate Brueghel family associated with 176P/LINEAR, the candidate 324P group associated with 324P/La Sagra, the candidate G1 group associated with P/2016 G1, and the candidate Tutenchamun family associated with (62412) 2000 SY178. Additionally, we identify three entirely new candidate families, the Interamnia family associated with P/2021 A5, the candidate 457P group associated with 457P/Lemmon-PANSTARRS, and the candidate Scheila family associated with (596) Scheila. We also reveal two newly identified family associations with known families between 259P/Garradd and the Adeona family, P/2019 A4 and the Jones family. All main-belt comets (MBCs) are likely associated with young and primitive families. Some unstable MBCs, which cannot be identified using HCM, may still originate from young and primitive families. However, due to dynamic diffusion, they cannot be conclusively linked to current families. Impact-disrupted asteroids could be linked with young families and they may change their original spectrum under the impact activity. Rotational fission of young and primitive asteroids might be a useful mechanism for facilitating the exposure of subsurface ice, and therefore triggering sublimation-driven activity. Rapid rotation and sublimation activity mechanisms are likely coupled. Therefore, further research should be made on such fast rotational asteroids that are located in primitive families.