Unraveling the mystery objects of the universe :Nuetron stars
Introduction.
Nuetron star is the collapsed core of a super massive giant star having a total mass of 10 – 25 solar masses and if metal rich the mass would be high. Nuetron stars have a radius of the order of 20 kilometers with a mass of about 1.4 solar masses. Nuetron stars are formed from the supernovae explosion of a star of large mass, combined with gravitational collapse. Nuetron stars are mostly composed of nuetrons and neutrinos. Nuetron stars have a surface temperature of about 600000 Kelvin. The gravitational field of nuetron star’s surface is about 200 billion times that of earth’s gravitational field.“To achieve the density of a nuetron star at home, just cram a herd of 50 million elephants into the volume of a thimble” – Astrophysicist Niel de grasse Tyson.
Formation of nuetron stars
Stars exist only by the balance between the rate of fusion of hydrogen into helium nuclei and the self gravity of the stars, when the helium is exhausted, gravity tightens the star. The core of the Super giant star of large mass burns hotter and at high speeds, the outer layers of the star swell. The helium nuclei burns to form carbon nucleiburns to form neon burns to form oxygen and then oxygen is turned into silicon nuclei is then turned heavier nuclei like iron. Now, iron core cannot be fused but is crushed by its own gravity. The high pressure at the core converts the protons and nuetrons into nuetrons and neutrinos, when this happens suppose a iron ball the size of earth is the star it is squeezed to the size of a city on earth. Gravity pulls the outer layers in at a rate of 25 percent the speed of light finally the star explodes, this explosion is known as a supernovae explosion which outshines galaxies. The product of this explosion is a nuetron star (only if the star had a large mass at the time of explosion. Our sun cannot become a nuetron star as it doesn’t have that much of mass or of heavier nuclei).Its mass is million times the mass of earth but compressed as an spherical object of a radius of about 25 km. Light bends around and hence you would be able to see the front and parts of back of the nuetron star. It has high density of mass except to the level of black hole and if it was denser it would have been a black hole rather than a nuetron star.
Structure of a nuetron star
Unlike stars, nuetron stars have an atmosphere, solid crust, liquid core just like planets.The outer part of the crust is made up of iron nuclei in a crystal lattice where electrons flow through them. The atmosphere is made up of hydrogen, helium and carbon. The base of crust is of liquid phase called as sphagetti phase and deeper it becomes lasagna phase. The lasgana phase is known as nuclear pasta, which is the strongest material in the universe, the core consists of quark – gluon plasma, the properties of this quark-gluon plasma is unknown to us.
Discovery of nuetron star.
In September 1967 when Jocelyn Bell (at that time a research student at Cambridge University). She was studying distant radio sources with a special detector, created and designed by her advisor Anthony Hewish in order to study rapid variations in radio signals. While doing so in the constellation of Vulpecula she found a rapid, intense and extremely regular pulses of radio waves from a single source. This made scientists to believe that it is from an advanced alien civilisation. But as it became more common to observe these kinda pulses, the sources was called pulsar or pulsating radio sources which is also a nuetron star. She discovered the pulsar PSR B1919+21.
Light house and nuetron stars.
If you view a light house from a ship, you would see a pulse of light at regular intervals of time, it would be like blinking when seen afar, such is a nuetron star(spinning).The nuetron star gives us a pulse of radiation each time the pulse is emitted in the direction of earth at equal intervals. Nuetron star is able to spin rapidly as it has a very less diameter (it can complete one full spin in a fraction of second). It is based on the Principle of Angular momentum.
Starquakes and nuetron stars
In the nuetron star we know that there is a solid crust and liquid core just like our planet, the solid crust is also broken up like tectonic plates and so starquakes just like our earth quakes, when starquakes happen the nuetron star (usually a Magnetar) releases a blast of radiation which can be seen clearly across our galaxy. On December 27, 2004, several satellites and telescopes detected an explosion which is a result of a starquake on the surface of SG1806-20R , a neutron star 50,000 light years away. The resulting flash of energy lasted only a tenth of a second but it released energy equivalent to the energy that the sun emits in about 150000 years!!. The star quake had a frequency of 94.5 hertz. In a star quake of a Magnetar the quake magnitude would be 23 in a standard scale.
Pulsars and Magnetars.
Pulsars and Magnetars are also nuetron stars. We know that when a nuetron star spins giving out radiation from a small part it becomes a pulsar. When the nuetron star produces very strong magnetic fields of about 10^9 to 10^11 tesla, it becomes a Magnetar. A Magnetar emits very strong bursts of X-rays and gamma rays. The active life of a magnetar is short and is only for about 10,000 years. But during thier short span they are said to have a magnetic field of a quadrillion gauss, this magnetic field is so strong that within 1000 kms of a magnetar, lifeforms would be torn into atomic scale and even influence the atomic physics of such atoms. But you would not have to worry about it as the nearest Magnetar is about 9000 light years in the constellation carina.
Pulsars pulsating regularly in milliseconds are used to test theory of general relativity in conditions of intense gravitational field. Pulsars are also the sources of ultra high energy cosmic rays.
Conclusion
Nuetron star are the only known dense objects which is normal unlike black holes which isn’t. After the supernovae if it’s density is more it is likely to become either a black hole or a nuetron star. In September 2019 we have discovered the most massive nuetron star which is the pulsar J074+6620. It is about 4600 light years away from earth. The nuetron stars still fascinate us with its properties. We still don’t know what exactly the core of a nuetron star is made up of. It’s properties still unknown.
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