Meteoroid, bolide and meteorite ?Chelyabinsk?

摘要

This paper presents the brief review of Chelyabinsk group of meteoroid, bolide and meteorite "Chelyabinsk" investigations. Height of the maximum of the main flash of Chelyabinsk bolide is 30 km. Only 1% of meteoroid mass arrived to the Earth surface in the form of meteorites while the most part of meteoroid became dust. During four days the dust had circumnavigated the globe and formed stratospheric dust belt. This new dust belt, located above the Junge aerosol layer, has persisted over at least a three-month period. The mass distribution of found meteorites is lognormal. This shape argues that fragmentation process of initial body happened randomly and in a cascade way. Transparent or translucent mineral filaments firmly linked to the particles were found in the meteoritic dust. In metallic phases of the meteorite mainly Fe-rich compounds exist. Very interesting topics of next research are magnetic properties of Fe-Ni phase, because of cosmic synthesis conditions. Meteoroids like "Chelyabinsk" fall on average once every 30 years. Therefore the problem of "asteroid and comet danger" should be expanded to the problem of "meteoroid, asteroid and comet danger".