Neutron stars. Stellar remnants that have reached the end of their evolutionary journey through space and time . They form when large stars run out of fuel and collapse.
Summary
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- 1 Birth
- 2 Training
- 3 Features
- 4 Pulsars
- 5 Sources
Birth
These interesting objects are born from previously giant stars that grow four to eight times the size of the Sun before exploding in catastrophic supernovae . After the explosion, the outer layers of a star are thrown into space, the core remaining but without causing nuclear fusion again . With no outer pressure from the fusion to counteract the inner pull of gravity , the star condenses and collapses.
Despite their small diameter (around 12.5 miles, or 20 km), neutron stars can boast about 1.5 times the mass of the Sun, making them incredibly dense. A single lump of neutron star matter the size of a sugar cube would weigh a hundred million tons on earth .
Training
For a neutron star to form, a star with a mass of about 1.5 to 5 times the mass of the Sun is needed . If the star has less than 1.5 solar masses, then it will not have enough matter or gravity to compress the object enough. You will only get a white dwarf , which is what will happen to the Sun one day.
On the other hand, if it has more than 5 times the mass of the Sun, the star will end its days as a black hole. But if the mass of the star falls between those mentioned above, then a neutron star will emerge.
Neutron stars are formed when the star runs out of fuel and collapses in on itself. Protons and electrons in atoms are forced to form neutrons. Since the star still retains a lot of gravity, any additional matter that falls on the neutron star is super-accelerated by gravity and converted into the same neutron material.
Just one teaspoon of a neutron star would have a mass greater than 5 x 1012 kg.
A neutron star actually has different shells. The astronomers believe that has an outer layer of nuclei atomic electrons, about 1 m thick. Beneath this crust, there are nuclei with a higher number of electrons. These would decay rapidly on earth, but the intense pressure of gravity keeps them stable.
When a neutron star forms, it preserves the momentum of the entire star, but because it is now only a few kilometers across, it rotates at enormous speeds, often as fast as hundreds of times per second.
The almost incomprehensible density of a neutron star causes protons and electrons to combine into neutrons – the process from which they take their name.The composition of their nuclei is unknown, but it is likely that they consist of a neutron superfluid or some state of the neutron. unknown matter.
Neutron stars contain an extremely strong gravitational pull, much greater than that of the earth. This gravitational force is particularly impressive given the star’s small size.
During their formation, neutron stars rotate in space. As they compress and shrink, the spiral spin speeds up due to the conservation of angular momentum, the same principle that causes a skater to spin faster as she approaches her arms to chest .
Characteristics
The main characteristic of neutron stars is that they resist gravitational collapse through the degeneracy pressure of the neutrons, added to the pressure generated by the repulsive part of the strong nuclear interaction between baryons. This is in contrast to main sequence stars, which balance the force of gravity with the thermal pressure caused by thermonuclear reactions within them.
It is not known whether the core of a neutron star has the same structure as its outer shells, or whether it is instead made up of quark_gluon plasma. The truth is that the very high densities that occur in the central area of these objects are so high that they do not allow valid predictions with computer models or experimental observations.
Pulsars
Neutron stars that have such a position cause the light beam to point directly towards the earth causing a pulsation to be seen. This happens because when the radiation beam is pointed at the ground, it is detected, but while turning around, the beam is pointing in another direction and is not visible on the ground; just like a lighthouse. Therefore, if anyone on earth has a wave receiver of Radio , he will receive regular pulses with the period equal to the rotation of neutron stars. This is why these types of neutron stars are called pulsars .
In 1967 the team of radio astronomers led by Antony Hewish , from the University of Cambridge , discovered pulsars, a work that earned him the Nobel Prize in 1974 , which were quickly associated with neutron stars by T. Gold in 1968. The explanation was based on the fact that the intense magnetic fields estimated for neutron stars (of the order of 1012 G) could account for the stability of the received pulses, and predicted that the frequency of the emitted pulses should slowly decay over time, due to the loss of rotational energy: this was later verified by discovering the decrease in the frequency of the pulses of the Crab Nebula pulsar . This argument was put on firm theoretical grounds by J. Ostriker and J. Gunn, in 1969 .
After spinning for several million years, pulsars run out of energy and turn into normal neutron stars. Few of the known neutron stars are pulsars. Only about 1,000 pulsars are known to exist, while there could be hundreds of millions of neutron stars in the galaxy .
The staggering pressures in the core of neutron stars could be like those that existed at the time of the big bang , but these states cannot be simulated on earth.
