  Dynamical features of a massive disk of distant trans-Neptunian objects are
considered in the model of the formation of small bodies in the Hill region of
a giant gas-dust clump that arose as a result of gravitational instability and
fragmentation of the protoplanetary disk. The dynamical evolution of orbits of
small bodies under the action of gravitational perturbations from the outer
planets and self-gravity of the disk has been studied for a time interval of
the order of a billion years. It is shown that the secular effects of the
gravitational action of a massive disk of small bodies lead to an increase in
the eccentricities of the orbits of individual objects. The result of this
dynamical behavior is the creation of a flux of small bodies coming close to
the orbit of Neptune. The change in the number of objects surviving in the
observable region of distant trans-Neptunian objects (the region of orbits with
perihelion distances of 40 < q < 80 AU and semimajor axes 150 < a < 1000 AU),
over time depends on the initial mass of the disk. For disks with masses
exceeding several Earth masses, there is a tendency to a decrease in the number
of distant trans-Neptunian objects surviving in the observable region after
evolution for a time interval of the order of the age of the Solar system, with
an increase in the initial mass. On the other hand, for most objects, orbital
eccentricities decrease under the influence of the self-gravity of the disk.
Therefore, the main part of the disk remains in the region of heliocentric
distances exceeding 100 AU.
