Positions of radiants of the modeled particles for different evolutionary times. The positions of radiants are shown in the same way as those in Fig. 1a. The P-R drag influenced the motion of modeled particles in this case. The strength of the drag characterized by parameter β was 0.001. The streams with the radiants in plots a)–f) were modeled for times 5, 10, 20, 30, 50, and 70 kyr in the past, respectively.