Because all the material that could rekindle it has run out - there is none left.
When a nebula collapses due to gravitational forces, the center becomes denser and hotter. As the material in the center becomes more compact, the pressure and temperature increase, eventually triggering nuclear fusion reactions that sustain a star's energy. This marks the birth of a new star in the center of the collapsing nebula.
A direct result of a star collapsing could be the formation of a black hole. This occurs when the core of a massive star collapses under its own gravity, creating a region of space with such strong gravitational pull that not even light can escape.
The equilibrium between the outward pressure of radiation and the force of gravity in stars enables them to maintain their size and shape. This balance prevents the star from collapsing under its own gravity or expanding due to the radiation pressure, allowing it to remain stable over a long period of time.
A star that has exhausted its supply of hydrogen will evolve into a red giant or supergiant, depending on its initial mass. Eventually, it may undergo a helium flash and fusion of heavier elements before collapsing into a white dwarf or supernova.
An old star collapsing in on itself, to put it in simple terms.
Because all the material that could rekindle it has run out - there is none left.
Super nova
"While the star can produce energy, that keeps the star in balance - it keeps the star from collapsing. By the way, another outward force is the gas pressure, but that, by itself, is not enough to counteract the force of gravity in the case of a star."
By a Star collapsing on its self.
hydrostatic
The death of a star is called a supernova or stellar explosion. This is a catastrophic event that occurs when a star reaches the end of its life cycle and can result in the star either collapsing into a dense core (neutron star or black hole) or completely exploding.
The balance of forces that keep a star from collapsing is called hydrostatic equilibrium. This equilibrium is maintained between the inward force of gravity and the outward force generated by gas pressure within the star.
Dynamic equilibrium.
When a nebula collapses due to gravitational forces, the center becomes denser and hotter. As the material in the center becomes more compact, the pressure and temperature increase, eventually triggering nuclear fusion reactions that sustain a star's energy. This marks the birth of a new star in the center of the collapsing nebula.
A direct result of a star collapsing could be the formation of a black hole. This occurs when the core of a massive star collapses under its own gravity, creating a region of space with such strong gravitational pull that not even light can escape.
The equilibrium between the outward pressure of radiation and the force of gravity in stars enables them to maintain their size and shape. This balance prevents the star from collapsing under its own gravity or expanding due to the radiation pressure, allowing it to remain stable over a long period of time.