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R. Sari, P. Goldreich (Caltech), Y. Lithwick (Berkeley)
At least several percent of large Kuiper belt objects are members of wide binaries. We argue that binaries formed during runaway accretion. Collisionless gravitational interactions provide two channels for binary formation. The initial step is always the formation of a transient binary when two large bodies penetrate each other's Hill spheres. Then, either dynamical friction due to small bodies or the scattering of a third large body can carry away the energy needed for permanent binding. We predict that most objects of size comparable to those currently observed in the Kuiper belt are members of multiple systems: outside of a critical separation of 3'', the binary probability is about 0.3%; inside that separation, the probability increases inversely with separation. This prediction is compatible with results from current surveys.
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Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.