Kinematic Tracebacks

Data is again restricted to the "bona-fide" sample from Malo et al. (2013). The point of a kinematic traceback is this: Our current definition of a moving group is a group of stars that formed from a single burst of star formation.

Because they are not gravitationally bound to each other, they are not clusters, but they should still be young enough that their motions are essentially undisturbed. Therefore, we can use their motions and an approximation of galactic orbits (here, an epicyclic approximation from Makarov et al. (2004) with updated Oort constants from Bobylev et al. (2013)) to find out where they were in the past. For a true moving group, all of the stars should have been fairly close to each other at the time of formation.