Hello!

I see subject hypervelocity stars is not very common here.
Just a few threads about it, years ago.

So if you're not familiar with them please read first
http://www.space.com/24432-hypervelocity-stars-ejected-from-milky-way.html

http://www.space.com/8801-superfast-star-shot-milky.html

Quote from article:
"None of these hypervelocity stars come from the center, which implies there is an unexpected new class of hypervelocity star — one with a different ejection mechanism."

I would like to share my hypothesis how this could happen (at least for some of them):
Hypervelocity star (or two not joined together yet, but accelerated normal stars), ejected from center of galaxy, hit yet another star on their path, and joined together with it.
Because of having to conserve momentum, it appears coming from different location than center of galaxy..

So precise analyze of path in the past of these stars will tell where they approximately hit something, using typical velocities at given radius from center of galaxy.

 

Best Regards!

 

Collisions of stars are exceedingly rare in the general galactic plane, and quasi-collisions too, where the path is strongly altered. This gets even rarer when the speed increases.