Tidal Distortion and Disruption of Earth-Crossing Asteroids

Tidal encounters of ellipsoidal granular asteroids with planets

“…Using a simplified approach allows us to explore in detail the mechanics of asteroid's deformations and disruptions during planetary encounters. We also compare our results with those obtained by Richardson et al (1998) who used a large numerical code. We find that many of the features reported by them can indeed be captured by our rather simple methodology, and we discuss the reasons why some of our results differ from theirs.…”

“…We will demonstrate that much of the qualitative behavior obtained by Richardson et al (1998) can be achieved far more easily by this technique, thereby allowing many different materials to be investigated. We also discuss several reasons for those discrepancies that are seen between our results and those of Richardson et al (1998). Furthermore, the simplicity of our approach allows us to explore the mechanics of tidal encounters in detail.…”

“…Evidence is accumulating that asteroids might be granular aggregates lacking tensile strength (Richardson et al 1998(Richardson et al , 2002 that are simply held together by self-gravity alone. Such objects may be so fragile that they fragment during planetary fly-bys owing to tidal effects (Sridhar and Tremaine 1992, Asphaug et al 1994, Richardson et al 1998, Walsh andRichardson 2006).…”

“…In a pioneering numerical study, Richardson et al (1998) considered the breakup of bodies as they flew past planets, with the fragmentation occurring due to the combined effects of rotation, tidal torques (in case of asymmetric bodies) and tidal stresses. They modeled the body as a granular aggregate comprised of 247 smooth spheres that interacted with each other only through inelastic collisions and that were held together just by gravity.…”

“…We take the asteroid's initial shape to be a prolate ellipsoid with a 2 /a 1 = α = β = a 3 /a 1 = 0.6, as opposed to the choice of Richardson et al (1998), who used α = 0.6 and β = 0.55. However, we do not expect this simplifying assumption to cause major differences from their results.…”