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34. Meteor mass distribution from underdense-trail echoes

Published online by Cambridge University Press:  14 August 2015

M. Šimek  and
B.A. McIntosh
M. Šimek
Affiliation:
Astronomical Institute of the Czechoslovak Academy of Sciences, Ondřejov, and National Research Council, Ottawa, Canada
B.A. McIntosh
Affiliation:
National Research Council, Ottawa, Canada

Abstract

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The amplitude of meteor echoes is recorded on a logarithmic scale by a high-power radar equipment (λ = 9·2 m, PT=3 MW, G = 5·6) at Springhill Meteor Observatory near Ottawa. The smallest amplitude measured corresponds to a pulse power of 10−12 W, which represents a minimum electron line density of about 7 × 1011 el/m or a radio magnitude of + 10.

Distribution curves of number of echoes as a function of echo power have been obtained from some 50 samples of 500 meteors each, at various times of day on about 1 day per month. The slopes showed little variation throughout the year. The statistical error in the slope value for any one sample was small, ~ 2–3%. However, determination of the mass index s from these slopes involves several problems. On the basis of simplest theory we have obtained for the sporadic background, with no definite seasonal or diurnal variation.

During shower periods, lower values of s were obtained. For the 1966 Leonids, s for the shower was determined by estimating the percentage of shower meteors in the total sample. A value s = 1·7 ± 0·1 was obtained as the mean of 6 samples. It is not known to what extent the height-ceiling effect influences the observation of this shower.

Type
Session 6
Information
Symposium - International Astronomical Union , Volume 33: Physics and Dynamics of Meteors , 1968 , pp. 362 - 372
Copyright
Copyright © Reidel 1968 

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