We've just learned about the life cycle of stars in our science class, but my teacher could not remember part of the massive star cycle: what determines the path a supernova takes, either as a neutron star or a black hole?
So.... what determines the supernova's path?
So.... what determines the supernova's path?
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This is down to the mass of the star's core section after it has shed the outer envelope of gasses in the supernova.
The core collapses because thermal pressure is no longer enough to hold the star in Hydrostatic Equilibrium. As the core collapses, it requires a new 'cold pressure' to hold it up. If the core is less than roughly 1.44 times the mass of the sun, then 'Electron Degeneracy Pressure' takes hold and keeps the stellar remains in hydrostatic equilibrium and forms a white dwarf.
If the core has a mass bigger than this, it continues to collapse, becoming smaller and denser. This is known as The Chandresekhar Mass Limit. As the star collapses further, Heisenberg's Uncertainty Principle tells us that the speed of the electrons must be increasing. They eventually begin moving at close to the speed of light, and become 'Relativistic'. Once the electrons become relativistic, they can no longer provide the degeneracy pressure required to hold the star. A new source of pressure is needed to counter gravity. This is when Proton or Neutron Degeneracy Pressure comes into play. These sorts of stars are known as Neutron Stars, as they are held in hydrostatic equilibrium by neutron degernarcy pressure.
Above around about 3 solar masses, The Oppenhiemer-Volkhov Limit, the neutrons and protons in the star also become relativistic as the star collapses further and further. Above this limit, there is no other source of pressure that can hold a star in hydrostatic equilibrium. The result is a black hole.
The core collapses because thermal pressure is no longer enough to hold the star in Hydrostatic Equilibrium. As the core collapses, it requires a new 'cold pressure' to hold it up. If the core is less than roughly 1.44 times the mass of the sun, then 'Electron Degeneracy Pressure' takes hold and keeps the stellar remains in hydrostatic equilibrium and forms a white dwarf.
If the core has a mass bigger than this, it continues to collapse, becoming smaller and denser. This is known as The Chandresekhar Mass Limit. As the star collapses further, Heisenberg's Uncertainty Principle tells us that the speed of the electrons must be increasing. They eventually begin moving at close to the speed of light, and become 'Relativistic'. Once the electrons become relativistic, they can no longer provide the degeneracy pressure required to hold the star. A new source of pressure is needed to counter gravity. This is when Proton or Neutron Degeneracy Pressure comes into play. These sorts of stars are known as Neutron Stars, as they are held in hydrostatic equilibrium by neutron degernarcy pressure.
Above around about 3 solar masses, The Oppenhiemer-Volkhov Limit, the neutrons and protons in the star also become relativistic as the star collapses further and further. Above this limit, there is no other source of pressure that can hold a star in hydrostatic equilibrium. The result is a black hole.