Zidian Wu

P/Giacobini-Zinner and the Draconid meteor shower

Abstract The two most spectacular meteor showers in the present century were probably the Draconid showers of 1933 and 1946. Lesser showers were also observed in 1926, 1952 and 1985 but none in other years. All the observed showers occurred when the parent comet, comet Giacobini-Zinner with a period of about 6.5 yr, was close to the Earth, leading naturally to the suggestion that the stream is young with meteoroids mostly located close to the parent comet. Aninteresting question remains, however—why showers only occurred in some of the years when the comet was close to the Earth and why a much higher level of activity occurred in 1933 and 1946. We analyse the data on the observed showers and investigate the dynamical behaviour of the Draconid meteoroid stream by means of a computer simulation. Five hundred large meteoroids (0.25 cm) and 500 small meteoroids (0.03 cm) were ejected at each perihelion passage of comet Giacobini-Zinner from 1900 to 1985 and their equations of motion were integrated forward to 1985 (the last well recorded shower). The cross-section of the stream in the ecliptic and the profile of the stream are analysed. We conclude that the best agreement between observation and theory is obtained if the meteoroids producing the shower are very young, released from the comet at that apparition.

The use of the distribution of the orbital energy to investigate the evolution of the Perseid meteoroid stream

Numerical integration of a meteor stream over a long period is a very time consuming process, especially if a number of different models have to be investigated. In this paper we demonstrate that using the distribution of orbital energy as a vector in a Markov process can be a useful tool and that meaningful results can be obtained with far less computation than is normally required.