The Use of Geocentric Variables to Search for Meteoroid Streams and Their Parents

A set of geocentric variables suitable for the identification of meteoroid streams has been recently proposed and successfully applied to photographic meteor orbits. We describe these variables and the secular invariance of some of them, and discuss their use to improve the search for meteoroid stream parents.

Dynamical Aspects of the Taurid Meteor Complex

Unusually long activity of the Taurid meteor complex, extending over 3-5 months according to new estimations based on various orbital similarity criteria, has been evoking controversies about the possible origin and dynamical evolution of this unique complex of meteor streams. It even casts doubts on the reality of the extension of the complex. In the present paper orbital elements and the extension of the Taurid meteor complex are re-examined on the bases of the most precise photographic meteor orbits available from the IAU Meteor Data Center in Lund. The results are evaluated and discussed from the viewpoint of various proposals on the origin and dynamical evolution of the complex.

A Study of Meteor Orbits Obtained in Japan

A list of 325 two-station photographic meteor orbits obtained with 35 mm cameras has recently been published by Japanese amateur groups. The present study analyzes the data and concludes that the orbits are of high quality and very useful for scientific purposes.

The Distribution of 1/a in Photographic Meteor Orbits

A study is made of the distribution of reciprocal semi-major axis in photographic meteor orbits. A detailed classification of the orbits is made according to quality. The distribution of 1/a in precise orbits is multimodal with two broad maxima approximately centered on 0.05 and 0.40 (AU)-1. Minima in the distribution appear near 0.20 and 0.66 (AU)-1 corresponding to Jupiter’s and Mars’ position in the 1/a, diagram. Considerable fine structure appears in the 1/a distribution. Resonance gaps corresponding to commensurabilities with Jupiter are detected. The gaps are similar to the well studied Kirkwood gaps in the asteroid beli.