- #36
JMz
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All good questions, but all the ones that matter to the OP were presumably factored into the estimate that there are 100M BH's in the MW.snorkack said:Analyze the statistics a bit:
Almost all M and K dwarfs ever formed are still around - the world has not lasted long enough for any of them to burn out. The only possible fates have been stellar collision or ejection from Milky Way, both of them rare.
Oldest G dwarfs are now burning out.
And for F, A, B and O dwarfs, the dwarfs presently existing are a small fraction of stars that have existed and burnt out.
Furthermore, the star formation rate of Milky Way has not been constant - young Milky Way at some time held more young stars at one time than now.
Now, what becomes or these short lived dwarfs?
G, F and A dwarfs become white dwarfs.
Above a certain mass, stars commonly become neutron stars.
What becomes of them?
Neutron stars can be destroyed by merger.
Also many pulsars have high peculiar velocities.
It appears that the formation of neutron stars often (not always) gives them high peculiar velocities.
Which fraction of pulsars in Milky Way are bound thereto? Which fraction of neutron stars formed in Milky Way is left in Milky Way?
What is the minimum mass of star to form a black hole rather than neutron star?
Does formation of black holes tend to give holes initial peculiar velocities, like the formation of pulsar does? How does the distribution of black hole initial peculiar velocities compare against the distribution of pulsar initial peculiar velocities?
Which fraction of black holes formed in Milky Way are left in Milky Way?