Black Hole Formation
Formation of Stellar Mass Black Holes
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!