Characteristics of Radio Echoes from Meteor Trails II: The Distribution of Meteor Magnitudes and Masses

Magnitude and mass distributions are deduced from radio echo data for sporadic meteors and for various meteor showers. The frequency of sporadic meteors is found to increase by 2.5 times per unit increase in magnitude over the range 0 m -10 m . This corresponds to an inverse square law for the differential mass distribution. Results obtained for shower meteors in the magnitude ranges 0 m to 2 m and 5 m to 7 m cannot in general be represented simply by an inverse power law of meteor masses with constant exponent s . The Arietids are found to have s >2 over the whole range of magnitudes investigated whereas the Perseids, Quadrantids and Geminids appear to have s <2 for the faint and s greater, similar 2 for the bright meteors. We conclude that the greater part of the total meteoric mass is contributed by the following ranges of magnitudes: Arietids, fainter than 7 m ; Perseids, Quadrantids and Geminids, 2 m to 5 m . In the case of the Geminids, the concentration of meteoric mass into this magnitude range appears to increase during the course of activity of the shower. Good agreement is found between radio, telescopic and visual data.