Dynamics of the clumps partially disrupted from a planet around a neutron star

Tidal disruption events are common in the Universe, which may occur in various compact star systems and could account for many astrophysical phenomena. Depending on the separation between the central compact star and its companion, either a full disruption or a partial disruption may occur. The partial disruption of a rocky planet around a neutron star (NS) can produce kilometer-sized clumps, but the main portion of the planet can survive. The dynamical evolution of these clumps is still poorly understood. In this study, the characteristics of partial disruption of a rocky planet in a highly elliptical orbit around a NS is investigated. The periastron of the planet is assumed to be very close to the NS so that it would be partially disrupted by tidal force every time it passes through the periastron. It is found that the fragments generated in the process will change their orbits on a time scale of a few orbital periods due to the combined influence of the NS and the remnant planet, and will finally collide with the central NS. Possible outcomes of the collisions are discussed.