1. Cemetary outbursts and the origin of meteor streams
Cometary outbursts, pointed out by Richter, are studied on the basis of recent investigations by Whitney. Unlike Whitney´s assumption of a uniformity of dimensions, a wide range of radii is supposed for the ejected particles. Assuming the distribution law N(s) ds ~ s^-4 ds to be valid over the range from 10^-5 cm to 1 cm, we obtain 7 . 10^11 g for the entire mass of particles ejected at an outburst The dynamical effect of such an outburst upon te comet´s morion is negligible. The ejected particles can produce a remarkable meteoric shower as long as they occupy a space of the same order of dimenstions as do the Draconids. A permanent stream cannot be generated by a single ouburst. In order to explain the existence of the Draconids, it is probably necessary to postulate an ejection of 10^11 g of meteors per revolution of the parental comet. This hypothesis seems to be plausible. Internal forces far fainter than those operating at the outburst would suffice to account for such a process. Slow ejections supposed here cannot manifest itselves in the motion of the comet, but they may be detected photometrically and spectroscopically.., 2. Ejection theory of the formation of the meteor streams
An analysis of the Draconids and Leonids shows that the ejection velocities are probably very low. In this case, simple formulae derived in 2.2. can be applied to in computing the orbits of the ejected meteors. The newly formed awarm is very thin, but the meteor become rapidly dispersed along the orbit of the ocmet. Four simple models of meteor awarms after ejection are considered and the distribution of meteors along the orbit investigated., 3. Local perturbations of meteor streams
An approximate analytical method is derived to account for local perturbations of meteor streams due to a close approach of a major planet. The cases of the Lyrids and Draconids are investigated. The great importance of planetary perturnbations is shown numerically. It is concluded that the Draconids observed in 1933 and 1946 could hardly have originated before the close approach of the parental comet to Jupiter in 1898., 4. Mass and density of meteor streams
A method of calcularing the total mass and density of meteor streams is developed and applied to the Draconids of 1933. From the visual and telescopic observations it is found that the probable mass of this awarn is of the order of 10^12 g. Although the spatial density inside the concentrated cloud is considerable, the total mass is far lower than that of the Geminids or Perseids. This, again, may be due to the fact that the stream is still being formed., and Článek je rozdělen do 4 kapitol, z nichž každá má samostatný abstrakt (na str. 5-6)
Mechanisms leading to higher particle concentrations in several places along the meteor stream associated with comet Halley are discussed. The positions of the mass concentrations represented by the mean anomaly of the stream orbit, as determined from long series of observations of the Orionids and Eta Aquarida, are correlated with the deviations in the semi-major axis and nodes of the evolving orbit of the comet. It is shown that random deviations in the orbital elements of the comet may be responsible for the nonstable mass concentrations in the stream.
The dynamical evolution of meteor stream particles in resonance appear to be affected by the same resonance mechanisms as rcsonant asteroids. Crossing of separatrix.like zones appears to be crucial for the formation of arcs and for the dissolution of streams.
Investigating the orbital evolution of known resonant meteor streams and of model streams, we have found examples for such a transitory are formation. The orbital inclination of a meteor stream appears to be a critical parameter for arc formation.