Published online by Cambridge University Press: 14 August 2015
At the early stage of evolution the meteoroid streams may be considered as elliptical rings of relatively small thickness. The influence of planetary perturbations can essentially increase the stream width and its thickness. As a result one stream may produce several couples of meteor showers active in different seasons of the year. 22 short-period meteoroid streams under review may theoretically produce 104 meteor showers. The existence of 67 is confirmed by observations.