Scientific Seminar of KhAO

Scientific Seminar

2000/03/02
Scattering Of Light By Composite Particles Comparable With A Wavelength, And Their Approximation By Systems Of Balls
Zubko E.S., Shkuratov Yu.G.
The scattering properties of ensemble of the independent randomly oriented systems consisting of two touching dielectric particles of the spherical and random shape by the size about a wave length are explored. Is shown, that the optical properties of such ensemble, are determined by properties of separate a buielder of the systems; the role of collective effects thus is small. Systems consisting of two balls, at major scattering angles shapes a negative branch of a degree of linear polarization, if the separate ball also shapes it, but systems composed by equivalent particles of the casual shape, does not discover a negative branch. The deduction is made that the modeling of scattering properties of not spherical and aggregate particles by systems consisting of balls by the size about length of a light wave is not adequate.

2000/02/10
Project of KhAO Homepage
Korokhin V.V., Beletsky S.A., Marchenko G.P., Shaparenko E.F., Velikodsky Yu.I.
Some principles of KhAO HomePage are formulated. Project of KhAO HomePage is presented.

2000/02/03
On the Near-Earth Asteroid Origin
D.F.Lupishko and T.A.Lupishko
It is generally recognized that main-belt asteroids (MBAs) and the 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 comparison of physical properties of NEAs and MBAs (and partly of comet nuclei) in order to understand what the physical properties of NEAs can tell us about their sources of origin was carried out in this paper. The principal results of such comparative analysis can be reduced to the following: the small sizes of NEAs, almost the same variety of taxonomic classes, the same mineralogy and predominance of differentiated assemblages among them, approximately the same shapes and rotation, optical properties and surface structure as compared to those of MBAs, all these 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 which are the most probable candidates for the cometary origin are pointed out.