|MadSci Network: Astronomy|
Models of galaxy collisions generally show that most of the stars stay in the merged system, but a considerable number of stars are ejected as well.
Most of the ejected stars arise from the outer parts of each galaxy in the collision. These stars are less strongly bound to the system by gravity.
In direct observations of large collisions, it is possible to see a plume of light from the ejected stars. You may want to read this article on the subject. The article states a result from theory, namely that about half the ejected stars will eventually fall back into the merger.
My hunch, therefore, is that it's not likely the Sun would be ejected in the upcoming collision of the Milky Way and Andromeda.
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