What prevents a star from collapsing after stellar death?

[D H]

So correct me if I am wrong. If a star has mass greater than the Chandrasekhar Limit, due to this greater mass the gravitational force is more (Moon has lesser gravity than Earth because mass of Moon is lesser than mass of Earth. So grater the mass greater the gravitational pull). So degeneracy pressure provided by the electrons is weaker than the inward pull of gravity. So when this mass is very less the schwarzschild radius is also less. So when the radius of the star falls below the schwarzschild radius then we get a black hole.

Am I right?

Not quite.

The Chandrasekhar limit is not the boundary between a star and a black hole. This limit pertains to white dwarfs, burnt-out stars that are mostly carbon and oxygen and in which electron degeneracy pressure sustains the balance between pressure and gravitation. There are many stars that are significantly more massive than the Chandrasekhar limit. In fact, a star whose initial mass is considerably larger than the Chandrasekhar limit is needed to produce a white dwarf that is close to the Chandrasekhar limit. Intermediate mass stars become rather leaky once they reach the red giant phase. They expel the majority of their mass into space as they burn helium.

The Chandrasekhar limit is instead the boundary between a white dwarf and neutron star. It is also very close to the point at which a growing white dwarf forms a type IA supernova. A white dwarf that has a binary pair can steal mass from its partner. A type IA supernova occurs when the mass of the dwarf gets close to the Chandrasekhar limit. The temperature builds and builds as the the white dwarf ever close to the limit, eventually reaching the point where carbon fusion starts. This triggers carbon fusion throughout the star, and that in turn triggers oxygen fusion. This all happens very quickly. Temperature rises to the point where temperature pressure dominates over radiation pressure and then over gravity. At this point, the entire star blows up.

 

[UncertaintyAjay]

A quantum state for an elecrron is defined by 4 quantum numbers. The first- the principle quantum number- tells you in which shell, the electron can be found.The second - the azimuthal quantum number tells you the orbital in which it is located. There are 5 orbitals- s,p,d and f. The fifth- the g orbital is hypothetical. The azimuthal quantum number is 0, for s; 1 for p; 2 for d; 3 for f. An orbital can only hold two orbitals. So there are 3 degenerate p orbitals( orbitals with the same energy) , each containing 2 electrons, 5 degenerate d orbitals and 7 degenerate f orbitals. The magnetic quantum number tells you which of these degebrate orbitals the electron can be found in. The last number the spin quantum number doesn't have a classical analog. There is a spin up(+1/2) and a spin down(-1/2). Two electrons are in the same state if both of them have all four quantum numbers identical. This is forbidden by paukis excluskon principle.