Symposium: Small meteoric particles in the earth's neighborhood: Radar determination of meteor orbits

Author:
  • GHGerald S. Hawkins
    Gerald S. Hawkins
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Abstract
The development of the study of meteor orbits is described from the single station to the multistation systems. Meteor orbits are divided into two classifications, major streams and minor streams plus sporadics. The orbits of the major streams are similar in their distribution to the orbits of short-period and long-period comets, but the second group exhibits different characteristics. More than 99% of sporadic meteors with mass greater than 10 mg are moving in direct orbits. This unidirectional rotation is an important property of the particles in interplanetary space. At fainter magnitudes the results of the Harvard Radio Meteor Project and other researchers reveal an additional component. A large proportion of the smaller particles are moving in almost circular orbits tilted at a steep angle to the plane of the solar system. If this "toroidal group" represents a steady-state system then it is of considerable importance in cosmogony.