Variation of Nongravitational Parameters for Comet Encke as a Result of its Decay

M. G. Ishmukhametova, E. D. Kondrat'eva, V. S. Usanin.

Protecting the Earth against Collisions with Asteroids and Comet Nuclei, In: A. M. Finkelstein, W. F. Huebner, V. A. Shor (Eds) Proceedings of the International Conference “Asteroid-Comet Hazard-2009”, StP: Nauka, 139–145 (2010)

Ключевые слова: Very Long Baseline Interferometry (VLBI), Near Earth Objects (NEOs), comet Encke, variations of nongravitational parameters, Marsden's model, secular decay, deposition of a substantial nonvolatile mass, to imped the sublimation, a little-massive mantle, to shrink the effective area linearly, to shrink the area exponentially, adequacy of models

Аннотация

An assumption is made that variations of nongravitational parameters of comet Encke in Marsden's model are caused by its secular decay. To account for decrease of nongravitational parame-ters three variants of physical processes are proposed: 1) deposition of a substantial nonvolatile mass not impeding the sublimation; 2) generation of a little-massive mantle shrinking the effective area linearly; 3) generation of a little-massive mantle shrinking the area exponentially. The corresponding equations are derived. The adequa-cy of the first two models over more than 150 years is shown