It is generally recognized that main-belt asteroids (MBAs) and nuclei of extinct comets are two main sources for the near-Earth asteroids (NEAs) replenishment. Theoretical studies of NEA dynamics and numerical modelling of their orbital motions showed that so-called resonance mechanism for supplying NEAs is quite sufficient to sustain this population. The physical properties of NEAs and MBAs (and partly of comet nuclei) were compared to understand what the physical properties of NEAs can tell us about sources of their origin. The results of the comparison are given in this paper. The principal results of such a comparative analysis can be reduced to the following. All the NEAs have the small sizes, almost the same variety of their taxonomic classes and mineralogy, predominance of differentiated assemblages among them, approximately similar shape and rotation, optical properties and surface structure as compared to those of MBAs. All these conclusions clearly indicate that the main asteroid belt is the principal source of NEA, and comet nuclei contribution to the total NEA population does not exceed 10%. The NEAs 2100 Ra-Shalom, 2101 Adonis, 2201 Oljato, 2212 Hephaistos, 3200 Phaethon, 3552 Don Quixote and 4015 Wilson-Harrington are the most probable candidates for the cometary origin.
Kinematika i Fizika Nebesnykh Tel Supplement
- Pub Date:
- September 2000