CAOSP abstracts, Volume: 22, year: 1992

Abstract: This paper is a reaction to the attempts to determine the ejection velocities of meteor particles from cometary nuclei using the statistics of photographic meteor orbits. It is argued that this is essentially impossible. The original dispersion velocities are masked completely by much larger measuring errors, and for all permanent meteor showers also by the accumulated effects of planetary perturbations. The perturbations, appearing after sufficient spread particles along the orbit, are on the average about 25-times more effective in the direction perpendicular to the orbital plane than in the direction of motion, and they are about 50-times more effective for typical comets of Jupiter family than for those of Halley type. The latter disproportion is responsible for the widely different distribution of the revolution periods of comets, annual meteor showers, and temporary meteor storms. In addition to direct spacecraft measurements, the only feasible sources of information on the ejection velocities are meteor storms, like the Draconids or Leonids, appearing only several times per century, and the cometary dust trail discovered by IRAS. Both of them indicate incomparably lower velocities than the meteor data - only a few meters per second - and a substantial role of the solar radiation pressure in the initial dispersion.

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