Rubble Pile Asteroids

• Published in: Annual review of astronomy and astrophysics Vol. 56; no. 1; pp. 593 - 624
• Main Author: Walsh, Kevin J
• Format: Journal Article
• Language: English
• Published: Palo Alto Annual Reviews 14-09-2018; Annual Reviews, Inc
• Subjects: Asteroids; collisional evolution; Earth; Earth orbital rendezvous; Earth orbits; Evolution; Flyby missions; Observational studies; Orbits; Planets; Population studies; Porosity; rubble pile; Solar system; Solar System formation; Space rendezvous; Spacecraft; Void space; Wavelengths
• ISSN: 0066-4146; 1545-4282
• DOI: 10.1146/annurev-astro-081817-052013

The moniker rubble pile is typically applied to all Solar System bodies >200 m and <∼10 km in diameter; in this size range, there is an abundance of evidence that nearly every object is bound primarily by self-gravity, with significant void space or bulk porosity between irregularly shaped constituent particles. The understanding of this population is derived from wide-ranging population studies of derived shape and spin, decades of observational studies in numerous wavelengths, evidence left behind from impacts on planets and moons, and the in situ study of a few objects via spacecraft flyby or rendezvous. The internal structure, however, which is responsible for the name rubble pile, is never directly observed but belies a violent history. Many or most of the asteroids on near-Earth orbits and those most accessible for rendezvous and in situ study are likely by-products of the continued collisional evolution of the main asteroid belt.