Extinct comets and asteroid-meteoroid complexes

Abstract

Modern concepts of the formation and evolution of meteoroid streams formed by the disintegration of cometary nuclei are described. The action of planetary perturbations determining the evolution of meteoroid orbits is discussed. On an example of the calculation of secular orbital perturbations of the asteroid 2003HP32, the main regularities in variation of the orbital elements as well as of the radii-vectors of ascending and descending nodes are found. The dispersion of orbits increases with time, and meteoroid streams may generate up to eight meteor showers observed on the Earth depending on the orbit type of the parent comet. It was established that some meteoroid streams include large fragments of extinct cometary nuclei. These fragments being the members of meteoroid streams are identified among the near-Earth asteroids. Consequently, the meteoroid streams consist of not only small particles but also of large fireball-producing bodies. This fact is proved based on the example of three asteroid-meteoroid complexes revealed by the authors in recent years.