Dynamics In The System Of Mutiple Irregular Celestial Bodies

Irregular minor body systems are widely exist in the Solar system,including asteroids,comets,binary asteroid systems,triple asteroid systems,etc.This theis studies dynamical behaviours of the system consist of any number of irregular bodies,such as the continuation and multiple bifurcations of periodic orbit families,the collision and annihilation of equilibrium points in the potential of irregular bodies during the variety of parameters,the dynamics of transition and the capillary action on the surface of irregular minor bodies,the dust dynamics around the comet nucleus,as well the dynamics in the binary asteroid systems and triple asteroid systems,etc.The research paths of irregular minor bodies follow from less to more,simple to complex.During the calculation and continuation of periodic orbits in the potential of minor celestial bodies,this theis calculated periodic orbits with different topological cases,resonant ratio,and stability;studied the continuation of periodic orbits with mutiple parameters;found the behaviours of pseudo period-doubling bifurcation of periodic orbits,the behaviours of period-doubling bifurcation of resonant periodic orbits,and the phenomena of mutiple bifurcations of periodic orbits during the continuation.When studing the dynamical behaviours of equilibria during the variety of parameters,it is found that the collision and annihilation of equilibia exist if the parameters vary,the reverse process,the generation and seperation of equilibia are also exist if the parameters reverse change.A conserved quantity which is about the number of all equilibria of the minor celestial body is found and proved.The number of non-degenerate equilibria is found to be a odd number.In addition,this theis pointed out that there are several kinds of bifurcations of the collision and annihilation of equilibia,and found the saddle-node bifurcation and saddle-saddle bifurcation around asteroid(216)Kleopatra.Moreover,the transitional dynamics on the surface of minor celestial bodyes are invistigated,this study is useful for analyzing the transition of surface grains,the reshaping of surface,and the softlanding of spacecrafts,etc.Then the linearized equations and characteristic equations are derived.It is discovered that the number of non-degenerate surface equilibria is an even number,which is also a very importantconclusion.After that,this theis used the N-body model to simulate the gravitation environment of minor bodies,using the micro soft spheres to cover the surface of minor bodies to simulate the soils and rubbles,with this model,the transitional dynamics of grains on the surface are invistigated.It is found that the grain released above the flat surface or concave region on an irregular celestial body needs significant shorter trajectory and time before being static on the surface equilibrium,and the height of grains decrease rapidly.However,the grain released above the convex region on an irregular celestial body needs significant longer trajectory and time before being static on the surface equilibrium.The maximum height of next jump may be bigger than the maximum height of the current jump.The liquid height in a capillary on the surface of minor bodies is derived using the potential of the irregular body.The global distribution of liquid heights are computed and analyzed.Furthermore,the single celestial body is changed into binary asteroid systems;the dynamical behaviours in the binary asteroid systems are investigated.The relative equilibria of binary asteroid system are discussed.The conditions of relative equilibria of simplified binary asteroid systems and general binary asteroid systems are derived.The gravitational environments of several binary asteroid systems are discussed.The topography and geomorphology of binary asteroid systems,(243 Ida),(1089)Tama,and(1862)Apollo are also studied.The dynamics of multiple asteroid systems and the full sextuple-body system(134340)Pluto-Charon are invistigated.The dynamical equation are established,and the conditions of relative equilibria,partial gravitational locking,and the spin-orbit locked have been derived.The dynamical configurations of the five triple asteroid systems(45)Eugenia,(87)Sylvia,(93)Minerva,(216)Kleopatra,and(136617)1994CC,and the six-body system(134340)Pluto-Charon are calculated and analyzed.The calculation shows that the Pluto and Charon are gravitationally-locked,the orbit angular speeds and attitude angular speeds of Pluto and Charon are basic equality;however,the norms of attitude angular speeds are not constant,and both of attitude angular speeds of Pluto and Charon have a periodic variation.The period of attitude angular speeds of Charon is greater than that of Pluto.In the end,this theis ont only consider the gravitational field of the irregular body,but also consider its electric and magnetic fields;then the dynamical behaviours of large dust grains are investigated with considering the gravitational field of the irregularshape.Several dynamical laws of equilibria have been found in these three potentials.Some contents are generalizations of innovations in the above sections.It is found that there exist stable non-resonant periodic orbits,stable resonant periodic orbits and unstable resonant periodic orbits in the gravitational field and electrostatic field of comet 1P/Halley.