asteroid family

Asteroid families are groups of asteroids within the main belt that share similar orbital elements. These families are believed to have formed when a larger asteroid was shattered by a catastrophic collision. The fragments from this event then continued in similar orbits, creating a distinct cluster. Approximately 40% of larger asteroids belong to these families, with the proportion rising to 90% for smaller asteroids, as collisions tend to produce more small fragments.1

The three largest and most well-studied families are Eos, Koronis, and Themis. Each family is compositionally homogeneous, meaning its members share the same basic chemical makeup, suggesting they originated from a single parent body. It is theorized that some Earth-crossing asteroids and many meteorites that reach Earth are also fragments from collisions similar to those that formed asteroid families.1