We present a model of near-Earth asteroid (NEA) rotational fission andensuing dynamics that describes the creation of synchronous binaries and allother observed NEA systems including: doubly synchronous binaries, high- ebinaries, ternary systems, and contact binaries. Our model only presupposes theYarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroidgeophysics, and gravitational interactions. The YORP effect torques a "rubblepile" asteroid until the asteroid reaches its fission spin limit and thecomponents enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189,370-385). Non-spherical gravitational potentials couple the spin states to theorbit state and chaotically drive the system towards the observed asteroidclasses along two evolutionary tracks primarily distinguished by mass ratio.Related to this is a new binary process termed secondary fission - thesecondary asteroid of the binary system is rotationally accelerated viagravitational torques until it fissions, thus creating a chaotic ternarysystem. The initially chaotic binary can be stabilized to create a synchronousbinary by components of the fissioned secondary asteroid impacting the primaryasteroid, solar gravitational perturbations, and mutual body tides. Theseresults emphasize the importance of the initial component size distribution andconfiguration within the parent asteroid. NEAs may go through multiple binarycycles and many YORP-induced rotational fissions during their approximately 10Myr lifetime in the inner Solar System. Rotational fission and the ensuingdynamics are responsible for all NEA systems including the most commonlyobserved synchronous binaries.
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