Fragmentation and densities of meteoroids

The phenomenon of meteoroid fragmentation in the Earth's atmosphere was recorded repeatedly by means of different methods and especially using the photographic technique of instantaneous exposure. Among the four principal forms of fragmentation, the quasi-continuous fragmentation, i.e. a gradual release of the smallest fragments from the surface of a parent meteoroid and their subsequent evaporation, is most common. The analysis of photographic observations shows that a substantial fraction of meteoroids is exposed to this type of fragmentation. According to the theory of quasi-continuous fragmentation and on the basis of light curves of meteors photographed in Dushanbe (Tajikistan), the mean bulk densities of meteoroids belonging to six meteoroid streams and the sporadic background have been determined, which vary in the range from 0.4 g cm-3 (Leonids) to 2.9 g cm-3 (Geminids).