The three-body problem with zero initial velocities is called the free-fall problem, and the problem has been systematically studied by Russian and Japanese schools. It has been shown that triple collision points exist in various places in the initial value space, and that these have a big effect on the structure of the phase space. In the present report, we extend the problem to include angular momentum as a perturbation.
In our research, the amount of angular momentum is parametrized by the virial ratio. We perform orbit integrations for several values of the virial ratio and look for the distribution of binary collision curves. The distribution is expected to change because triple coliision points disappear in the inital value space. We discuss about the deviation of the distribution from that of the free-fall problem.