Institute of Theoretical Astronomy of RAS, nab.Kutuzova, 10, Saint-Petersburg, 191187, Russia
Variety of cometary orbits, considerable eccentricities and inclinations, makes it impossible to investigate analytically the orbital evolution of fragments of double cometary nucleus perturbed by the third body. Statistical or numerical-analytical methods seem to be preferable.
In [1] the averaged equations of motion of the binary comet fragments were derived under assumption, that within one revolution of the fragments around their centre of masses the perturbing function depends on the mean anomaly of the third body linearly.
In this paper the formulae for changing the elements of the smaller fragment with respect to the bigger one during its one revolution are derived accounting for: (i) nongravitational forces acting on the fragments; (ii) loss of the mass due to sublimation.
Evolution of the fragment orbit is studied by numerical integration of the averaged equations and the results are controlled by the accurate integration.
[1] Chernetenko Yu.A. Motion of the fragments of binary comets and asteroids. In: Dynamics, Ephemerides and Astrometry in the Solar System, IAU Symp. 172. Book of abstracts. 1995. p.60.