What is meant by electron degeneracy pressure?

[ dĭ-jĕn′ər-ə-sē ] A pressure exerted by dense material consisting of fermions (such as electrons in a white dwarf star). This pressure is explained in terms of the Pauli exclusion principle, which requires that no two fermions be in the same quantum state.

Is electron degeneracy pressure a force?

A2A: Electron degeneracy pressure is just the confined momentum of a concentration of fermions, who because of the exclusion principle have to stack up into higher momentum states rather than herding together into a low momentum state. But the exclusion principle isn’t a force, it is more like a mathematical identity.

How is electron degeneracy pressure different from neutron degeneracy pressure?

So, instead of electron degeneracy the neutron star is held up against collapse from neutron degeneracy with the main difference that the neutron degeneracy pressure is much higher. The same Pauli Exclusion Principle applies; a neutron must occupy its own quantum state (or space) and cannot be compressed further.

What is the neutron degeneracy pressure?

Neutron degeneracy is a stellar application of the Pauli Exclusion Principle, as is electron degeneracy. This creates an effective pressure which prevents further gravitational collapse, forming a neutron star.

Why is it called degeneracy pressure?

Since electrons cannot give up energy by moving to lower energy states, no thermal energy can be extracted. The momentum of the fermions in the fermion gas nevertheless generates pressure, termed “degeneracy pressure”.

What is electron degeneracy pressure in white dwarfs?

White dwarfs Electron degeneracy pressure will halt the gravitational collapse of a star if its mass is below the Chandrasekhar limit (1.44 solar masses). This is the pressure that prevents a white dwarf star from collapsing.

How does electron degeneracy pressure support a white dwarf?

What is supported by electron degeneracy pressure?

In particular, electron degeneracy pressure is what supports white dwarfs against gravitational collapse, and the Chandrasekhar limit (the maximum mass a white dwarf can attain) arises naturally due to the physics of electron degeneracy.

Which force is stronger electron degeneracy pressure or neutron degeneracy pressure?

But the neutron star collapse clearly happens at a higher mass than a white dwarf collapse. This would seem to imply that neutron degeneracy can support greater pressure than electron degeneracy.

How does gravity defeat electron degeneracy pressure?

Any solid object has its atoms kept apart by electron degeneracy pressure. If electron degeneracy pressure is overcome by gravity the object collapses and the electrons are expelled and the nuclei merge. The protons get converted into neutrons. This collapse can only happen in very massive objects.

Is white dwarf a supernova?

The most massive stars, with eight times the mass of the sun or more, will never become white dwarfs. Instead, at the end of their lives, white dwarfs will explode in a violent supernova, leaving behind a neutron star or black hole.

What is electron degeneracy pressure?

Electron degeneracy pressure occurs when electrons are compressed into a very small volume. Since their positions are well-known, they gain a large momentum in accordance with Heisenberg’s uncertainty principle. This momentum creates a pressure which is temperature-independent and can result in helium flash in stars.

How do you find the degeneracy pressure at zero temperature?

The degeneracy pressure at zero temperature can be computed as where V is the total volume of the system and Etot is the total energy of the ensemble. Specifically for the electron degeneracy pressure, m is substituted by the electron mass me and the Fermi momentum is obtained from the Fermi energy, so the electron degeneracy pressure is given by

How does electron degeneracy pressure stop a star from collapsing?

Electron degeneracy pressure will halt the gravitational collapse of a star if its mass is below the Chandrasekhar limit (1.44 solar masses). This is the pressure that prevents a white dwarf star from collapsing.

What is Chandrasekhar limit of electron degeneracy?

At the Chandrasekhar limit, the pressure exerted by the electrons travelling at close to the speed of light becomes insufficient to support the star, and the white dwarf collapses into a much denser state. Electron degeneracy occurs at densities of about 10 6 kg/m 3.