How are Neutron Stars Formed


How are neutron stars and black holes formed

Massive stars, which are roughly 8–15 times more massive than the Sun, die and become neutron stars.

The dense inner core is all that is left after a massive star collapses and erupts in a massive supernova explosion.

The core of the dying star becomes increasingly denser as it collapses.

Protons and electrons in the core eventually can no longer withstand gravity and combine to form neutrons.

The core’s entire composition eventually decays into neutrons, and there you have it.


Now in Detail

The gravitational forces that stars exhibit are widely recognized. 

This gravitational power is most intense at the star’s core, which is under tremendous pressure due to gravity. 

The question arises: why doesn’t the core collapse under this intense gravitational force? 

The answer lies in the intricate dance of nuclear fusion, energy, and the balance between opposing forces within the star.

Gravitational Equilibrium

At the heart of a star, its core faces an unrelenting gravitational force. 
However, this core does not simply collapse because of the energy generated by the fusion of hydrogen into helium. 
The immense pressure created by this nuclear fusion process acts as a counterbalance to the force of gravity. 
It’s a delicate equilibrium that sustains the star. 

The Marvel of Nuclear Fusion

Nuclear fusion is a remarkable process that goes beyond merely holding the star’s core together. 
It releases more energy than it consumes, making it self-sustaining up to a certain point – the production of the iron atom. 

Balancing Act

This continuous nuclear fusion not only generates substantial energy but also results in intense pressure within the star. 

This pressure, in turn, counteracts the gravitational forces, preventing the star from collapsing further. 

The March to Heavier Elements

As the star progresses in its life cycle, hydrogen fuses into helium, and this process continues with helium forming carbon, carbon transforming into nitrogen, and so on. 

Each step generates a substantial amount of energy, maintaining the star’s equilibrium. 

The Iron Paradox

However, a turning point arrives when iron production commences. 

Iron fusion consumes more energy than it releases. 
This marks the beginning of the star’s decline, as the core can no longer sustain itself through nuclear fusion. 

The Inevitable Collapse

With the depletion of hydrogen, helium, carbon, and other fusion materials, the balance between pressure and gravity is disrupted. 

The combined pressure generated by various fusion reactions in different parts of the star’s core can no longer withstand the relentless gravitational pull, initiating the star’s collapse. 

Stellar Endgame

For massive stars, this collapse leads to the core compressing into a singularity, birthing a black hole. 

In less massive stars, the collapse does not result in a black hole but rather in a neutron star, which is a less dense counterpart. 

The Role of Electron and Neutron Degeneracy Pressure

With iron-rich cores unable to produce energy to resist further collapse, a different form of pressure intervenes: electron degeneracy pressure. 

Put simply, two electrons cannot occupy the same space simultaneously. 
However, the outer shell of the star continues to burn, depositing more mass onto the core. 
As mass accumulates, gravity surpasses electron degeneracy pressure, causing further core collapse.

At this stage, temperatures are incredibly high, causing protons and electrons to combine and form neutrons. 

As the star’s collapse proceeds, these neutrons are squeezed into progressively smaller spaces, activating neutron degeneracy pressure. 
This force, akin to electron degeneracy pressure, prevents further collapse, especially in stars that aren’t excessively massive. 

Supernova and Neutron Star Formation

During this process, the immense gravitational pressure gives rise to an outburst of neutrinos, ejecting other materials into space in a spectacular supernova event. 

What remains is a structure of super-dense material that retains its shape. 
This structure essentially constitutes the core remnants of the parent star, boasting a density similar to atomic nuclei.

In essence, this is the birth of a neutron star, a celestial body with an extraordinary density, akin to a colossal atomic nucleus, and typically measuring a mere 10 kilometers in width.



The formation of a neutron star is a cosmic ballet involving the interplay of gravitational forces, nuclear fusion, and the intricate balance between various forms of degeneracy pressure. 

It is a testament to the remarkable processes that occur in the cosmos, producing these intriguing celestial objects.




If our sun dies, will it become another black hole


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