Emelianenko V. V. – Institute of Astronomy of the Russian Academy of Sciences
“Dynamic evolution of a self-gravitating planetesimal disk in the distant trans-Neptunian region”
The recent discovery of a family of objects moving far beyond the orbit of Neptune has sparked a heated discussion about the structure of the outer Solar system. In particular, the unusual grouping of the angular elements of the orbits of these objects near certain values became the basis for the hypothesis of the existence of a distant giant planet producing this effect in the works (Trujillo, Sheppard, 2014) and (Batygin, Brown, 2016). Although the dynamic picture looks quite convincing, the question of the actual existence of the ninth planet of the Solar System remains open. Despite intensive searches, the planet has not yet been discovered. The explanation of the formation of such a massive and distant planet also presents enormous difficulties. Therefore, there is a need to consider other scenarios for the formation of the observed structure of the distant trans-Neptunian region.
In our work, the long-term gravitational interaction of giant planets with the remnants of planetesimals that did not enter these planets is studied. The study is based on the numerical solution of the problem of N bodies over a time interval of the order of the age of the Solar System. It is shown that due to age-old resonances, distant trans-Neptunian objects appear in a wide range of initial masses of the planetesimal disk. This mechanism explains the origin of Sedna-type objects. The distributions of the orbital slopes for the observed objects and in the considered model have close average values (about 20 degrees). Thus, distant trans-Neptunian objects are a natural result of the long-term evolution of a system that includes migrating giant planets and a self-gravitating planetesimal disk.