Quote:
Originally Posted by Fred Brackin
The issue there is that those are already supernova remnants. Unless very ancient the supernova that produced the neutron stars would leave a bubble of hot gas the way the Geminga supernova did. I haven't heard of a detectable bubble besides the Geminga one in our neighborhood.
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Actually they are pretty common. In fact the Sun sits fairly close to the boundary of the Local Bubble and the Loop1 Bubble, which raises the local density a bit over both, though still vastly lower than the galactic average.
There's also quite a lot of debate over what supernovae were responsible, the Gemini gamma ray source is a popular candidate, but the irregular shape seems to point at several supernovae being involved. The other favorites are stars formed and since exploded in association with the Pleiades. In any case, as geologic things go, the Local Bubble is not particularly old, no more than a few 10s of millions of years. There's been lots of time for neutron stars to have formed around here long before it existed, and lots of time for ones formed quite far away to have moved into this vicinity or vice versa.