Some features of Geminid meteoroid disintegration in the Earth's atmosphere

Among 11 bright Geminid meteors photographed at the Institute of Astrophysics, Tajik Academy of Sciences (Dushanbe, Tajikistan), 3 displayed distinct high-frequency (more than 100 Hz) pulsations of brightness, or flickering. As a rule, for these Geminids, pulsations of brightness begin at the middle of their photographed path, at the height of about 75 km, and last until the end of the visible trajectory. Different possible meteoroid ablation mechanisms causing the flickering of the bright Geminids are discussed. The obtained results allow us to conclude that the observed high-frequency flickering of Geminid fireballs may be explained by an autofluctuating mechanism of the meteoroid ablation, i.e. by melting and cyclic ablation of the surface-layer of meteoric matter with the period corresponding to the observed period of the flickering.