  The microscopic framework of time-dependent covariant density functional
theory is applied to a systematic study of ternary quasifission in collisions
of pairs of $^{238}$U nuclei. It is shown that the inclusion of octupole degree
of freedom in the case of head-to-head collisions, extends the energy window in
which ternary quasifission occurs, and greatly enhances the number of nucleons
contained in a middle fragment. Dynamical pairing correlations, included here
in the time-dependent BCS approximation, prevent the occurrence of ternary
quasifission in head-to-head collisions, and have an effect on the location of
the energy window in which a middle fragment is formed in tail-to-tail
collisions. In the latter case, as well as for tail-to-side collisions, the
formation of very heavy neutron-rich systems in certain energy intervals is
predicted.
