The stellar members of the Sco–Cen association have nearly parallel velocity vectors, moving at about 20 km/s with respect to the Sun. The variation of velocity within the subgroups is about 1–2 km/s, and the group is most likely no longer held together by gravity. Several supernovae have exploded in Sco–Cen over the past 15 million years, leaving a network of expanding gas superbubbles around the group.