Good question.With that farthest star "nearly half the distance" to the Andromeda galaxy, are we sure which galaxy it is really "in"?
This is surprising. Do you have a source on this? Perhaps it’s the DM ratio that is less.Andromeda has more stars, but supposedly less dark matter, so is thought to have less total gravitational mass than the Milky Way.
Thanks UC."A spiral galaxy like the Milky Way, Andromeda contains a concentrated bulge of matter in the middle, surrounded by a disk of gas, dust, and stars and an immense halo. Though Andromeda contains approximately a trillion stars to the 250 billion in the Milky Way, our galaxy is actually more massive, because it is thought to contain more dark matter."
That sounds about right. The Wiki article (link now repaired) states there are about 100 to 150 billion stellar masses. This, no doubt, equates to a much larger number of stars since more stars are greater than one stellar mass, so as many as 1 trillion stars seems possible.Is that right? 250 billion stars to 1 trillion stars?
That seems to have been the estimate prior to 2018....(also from that Wiki link)Why are they described at close to the same mass?
Normally I would assume its motion would reveal its host galaxy, but perhaps not in this case since the free fall time is about 10E15 years, if I'm calculating that right -- Kepler's equation setting ecc. = 1, and Vi = 0.So, with the masses in question, it seems that just knowing the position of a star about midway between the two galaxies isn't enough information to tell us which galaxy the star "belongs to" (orbits?). Perhaps some measurements of the motion would be helpful.