My guess is from 10 million light years away, class M, K and G stars are invisable. If one was disrupted, it might look like an O, B, A or F star (for a few hours?) until the wound healed, or the stars rotation turned it, so about the normal number of photons were hitting our telescope lens = essentially none. Since collisions are very rare, perhaps none have occured within 10 million light years for us to observe.

I suppose the neutron star that collided with Earth, passed though the diameter and kept going. If exiting at 0.0001 c, I would think a very large exit hole and considerable heating of most of the rest of Earth. Neil