Catalog of Proper Orbits for 1.25 Million Main Belt Asteroids and Discovery of 136 New Collisional Families

TL;DR

This paper presents a comprehensive catalog of proper orbital elements for 1.25 million main belt asteroids, identifies 136 new asteroid families, and analyzes their characteristics and ages, enhancing understanding of asteroid collisional history.

Contribution

The study provides a new, extensive catalog of asteroid proper elements and discovers 136 previously unreported asteroid families, including the youngest known family and several formed within the last few million years.

Findings

Identified 136 new asteroid families in the main belt.

Discovered the youngest asteroid family formed 16-17 kyr ago.

Characterized several families' ages and formation processes.

Abstract

The proper elements of asteroids are obtained from the instantaneous orbital elements by removing periodic oscillations produced by gravitational interactions with planets. They are unchanging in time, at least if chaotic dynamics and non-gravitational forces could be ignored, and can therefore be used to identify fragments of major collisions (asteroid families) that happened eons ago. Here we present a new catalog of proper elements for 1.25 million main belt asteroids. We explain the methodology, evaluate uncertainties, and discuss how the new catalog can be used to identify asteroid families. A systematic search for families yielded 153 cases not reported in Nesvorn\'y at al. (2015) -- 17 of these cases were identified in various other publications, 136 cases are new discoveries. There are now 274 families in the asteroid belt in total (plus a handful of families in the resonant Hilda population). We analyzed several compact families in detail. The new family around the middle belt asteroid (9332) 1990SB1 (9 members) is the youngest family found so far (estimated formation only 16-17 kyr ago). New families (1217) Maximiliana, (6084) Bascom, (10164) Akusekijima and (70208) 1999RX33 all formed 0.5-2.5 Myr ago. The (2110) Moore-Sitterly family is a close pair of relatively large bodies, 2110 and 44612, and 15 small members all located sunwards from 2110 and 44612, presumably a consequence of the Yarkovsky drift over the estimated family age (1.2-1.5 Myr). A systematic characterization of the new asteroid families is left for future work.