High Velocity Star Formation in the LMC

Light-echo measurements show that SN1987A is 425 pc behind the LMC disk. It is continuing to move away from the disk at $18\text{kms}$. Thus, it has been suggested that SN1987A was ejected from the LMC disk. However, SN1987A is a member of a star cluster, so this entire cluster would have to have been ejected from the disk. We show that the cluster was formed in the LMC disk, with a velocity perpendicular to the disk of about $50\text{kms}$. Such high velocity formation of a star cluster is unusual, having no known counterpart in the Milky Way.