Asteroid family identification using the Hierarchical Clustering Method and WISE/NEOWISE physical properties

TL;DR

This study uses WISE/NEOWISE albedo data and hierarchical clustering to identify asteroid families in the Main Belt, improving confidence in family associations and contributing to understanding asteroid formation and distribution.

Contribution

It introduces a method combining albedo data with hierarchical clustering to identify asteroid families with higher confidence than dynamical methods alone.

Findings

Identified 76 asteroid families linking 38,298 asteroids.

Over one-third of the Main Belt population is in high-confidence family cores.

Albedo distributions differ significantly between family members and background objects.

Abstract

Using albedos from WISE/NEOWISE to separate distinct albedo groups within the Main Belt asteroids, we apply the Hierarchical Clustering Method to these subpopulations and identify dynamically associated clusters of asteroids. While this survey is limited to the ~35% of known Main Belt asteroids that were detected by NEOWISE, we present the families linked from these objects as higher confidence associations than can be obtained from dynamical linking alone. We find that over one-third of the observed population of the Main Belt is represented in the high-confidence cores of dynamical families. The albedo distribution of family members differs significantly from the albedo distribution of background objects in the same region of the Main Belt, however interpretation of this effect is complicated by the incomplete identification of lower-confidence family members. In total we link 38,298 asteroids into 76 distinct families. This work represents a critical step necessary to debias the albedo and size distributions of asteroids in the Main Belt and understand the formation and history of small bodies in our Solar system.