Relative motions and orbits of eight open clusters. (a) The colored dots represent the members of eight open clusters and the larger dots represent the centers of the clusters. The directions of the arrows for Pismis 5_A, Pismis 5_B, QZ 1, and NGC 2546 indicate the direction of motion with respect to Pismis 5. The length of the arrows represents the magnitude of the velocity. The arrow directions for Alessi 43 and BH 56 represent the direction of movement relative to Collinder 197, and the length of the arrow represents the magnitude of the speed. The gray error bars represent the velocity uncertainties in the X, Y, and Z directions. (b) The orbits of eight open clusters. The stars display the position before 5 Myr, whereas the solid lines depict the orbits from before that time to the present. The cluster positions after 10 Myr are indicated by the squares, while the dotted lines depict the trajectory from the present to that point. The gray trajectory is the result of 1000 simulations, meaning the uncertainties of the orbit.