Stellar mass black holes may be
produced by the collapse of the cores of massive stars during supernova
outbursts.
- initially, a smallish remnant forms--a remnant of mass on the order
of 1.4 M(Sun)--a neutron star
- a shock wave next propagates through the outer layers of the star
iginiting nuclear reactions and pushing on the envelope of the star
- depending upon the detailed structure of the envelope of the star, the
shock will eject the envelope or it will stall and allow some or all of the
envelope to fall-back onto the initial neutron star remnant
- if the material falls-back onto the star, then the mass of the remnant
increases
- neutron stars are like white dwarfs in the sense that as their mass
increases, they get smaller (denser) in order to generate the higher
pressure needed to counteract the effects of gravity
- this has the same consequence in that there is an upper limit for the
mass of a neutron star
- the upper limit is not as well-determined as for the white dwarfs as the
upper limit depends upon the nature of the nuclear (strong)
interaction which is not well-understood under the conditions found in
neutron stars -- the upper limit is 2 - 3 M(Sun)
- if the mass of the neutron star increases beyond 2 - 3
M(Sun), then the
neutron star collapses and forms a black hole -- after the neutron star phase
there is no known type of matter which can generate sufficient pressure to
overcome the effects of gravity and the star must then contiuously collapse
until it compresses to infinite density and zero volume!
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