On the origin of Triton and Pluto

  title={On the origin of Triton and Pluto},
  author={William B. McKinnon},
  pages={355 - 358}
Lyttleton hypothesized long ago that Triton and Pluto originated as adjacent prograde satellites of Neptune1. With the presently accepted masses of Triton and Pluto–Charon2,3, however, the momentum and energy exchange that would be required to set Triton on a retrograde trajectory is impossible. The mass of Triton has probably been seriously overestimated4,5, but not by enough to relax this restriction. It is implausible that the present angular momentum state of Pluto–Charon has been… 
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