On the oldest asteroid families in the main belt

Abstract

Asteroid families are groups of minor bodies produced by high-velocity collisions. After the initial dispersions of the parent bodies fragments, their orbits evolve because of several gravitational and non-gravitational effects,such as diffusion in mean-motion resonances, Yarkovsky and YORP effects, close encounters of collisions, etc. The subsequent dynamical evolution of asteroid family members may cause some of the original fragments to travel beyond the conventional limits of the asteroid family. Eventually, the whole family will dynamically disperse and no longer be recognizable. A natural question that may arise concerns the timescales for dispersion of large families. In particular, what is the oldest still recognizable family in the main belt? Are there any families that may date from the late stages of the Late Heavy Bombardment and that could provide clues on our understanding of the primitive Solar System? In this work, we investigate the dynamical stability of seven of the allegedly oldest families in the asteroid main belt. Our results show that none of the seven studied families has a nominally mean estimated age older than 2.7 Gyr, assuming standard values for the parameters describing the strength of the Yarkovsky force. Most "paleo-families" that formed between 2.7 and 3.8 Gyr would be characterized by a very shallow size-frequency distribution, and could be recognizable only if located in a dynamically less active region (such as that of the Koronis family). V-type asteroids in the central main belt could be compatible with a formation from a paleo-Eunomia family.

arXiv comment9 pages, 5 figures, 5 tables. Accepted for publication in MNRAS

References in corpus (11)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Solar System Objects Observed in the SDSS Commissioning Data
• The taxonomic distribution of asteroids from multi-filter all-sky photometric surveys
• Capture of Trojans by Jumping Jupiter
• Asteroid family ages
• Constraining the cometary flux through the asteroid belt during the late heavy bombardment
• A multi-domain approach to asteroid families identification
• Revising the age for the Baptistina asteroid family using WISE/NEOWISE data
• Dynamical evolution of V-type asteroids in the central main belt
• Dynamical evolution of the Cybele asteroids
• Dynamical evolution and chronology of the Hygiea asteroid family

Cited by in corpus (9)

• On the Ages of Resonant, Eroded and Fossil Asteroid Families
• An ancient and a primordial collisional family as the main sources of X-type asteroids of the inner Main Belt
• Asteroid Family Associations of Active Asteroids
• Yarkovsky V-shape identification of asteroid families
• Size-dependent modification of asteroid family Yarkovsky V-shapes
• Characterizing the original ejection velocity field of the Koronis family
• Scattering V-type asteroids during the giant planets instability: A step for Jupiter, a leap for basalt
• Influence of the Centaurs and TNOs on the main belt and its families
• V-type Near-Earth asteroids: dynamics, close encounters and impacts with terrestrial planets