http://earthsky.org/space/a-brilliant-but-solitary-superstar" mentions the possibility that a superstar, VFTS 682, might've been "ejected" from a nearby star cluster, R 136. Apart from my amazement about the sheer size (and temperature) of this star, I'm curious about what would have to happen for something so massive to be moved in any manner. I've little-to-no knowledge of astrophysics, so I'll do my best to follow, but the only thing I can think of at the moment would be an explosion. Hopefully I don't offend anyone with my attempts to make something that I'm sure is incredibly complex out to be so simple. Feel free to tell me if I'm in-over-my-head.