Neutron star | WHAT IS A NEUTRON STAR? | WHAT HAPPEN WHEN TWO NEUTRON STAR COLLIDE? |

What is neutron star? 

Neutron stars are formed when a giant star, about 8 to 30 times the mass of our Sun, bursts into a supernova.  

They are small, typically the size of an asteroid, about 20 kilometers in diameter, but with a mass that is about 1.40 times greater than that of our Sun.  

In that perspective, a cubic centimeter of neutron star material would weigh more than ten million tons!  But what is a neutron star. How is it born?

Let us understand a little more deeply about neutron stars.

Neutron stars are the dead remnants of a massive star and are almost entirely made up of neutrons.  

If you compress all humans on the planet into a small cup, the density will be the same as the density of a neutron star.  One teaspoon of neutron stars weighs as much as one billion tons.

We know that every object with a non-zero mass, although smaller mass, has gravity.  This gravity acts towards the center of the object, that is, the Earth's gravity pulls everything radially inward.

The mass of a star is very high, due to which the pressure and temperature are increasing as it moves towards its center.  When the pressure and temperature at the core of the star is sufficiently high, it can form the helium nucleus by joining the protons together.  This process is called thermonuclear fusion, 

what happens in an atomic bomb.  It releases tremendous energy.  Lighter elements are less stable than heavy elements.  So when they are linked together, they release energy to form a heavier element which is more stable.  This energy is nothing but light / radiation emanating from the star.

 This radiation exerts a radially outward pressure and balances radial inward acting gravity.  Due to this, the star retains its spherical shape.

 The star will keep shining until it has enough light elements to make it heavier.  They are connected in an onion-like sphere in this order: 

Hydrogen -> Helium -> Carbon -> Oxygen -> Neon -> Magnesium -> Silicon -> Iron.

Low-mass stars (up to 8 solar masses) can form elements up to oxygen and become a white dwarf.  Heavier stars make elements up to iron.

Iron is the most stable element.  After iron, the stability decreases.  Therefore, the iron nucleus does not have to release energy to make it more heavy nucleus, but rather it is needed.  Because of this when more fusion is not possible, there is no radiation pressure to balance gravity.  Gravity wins, and the star collapses in a spectacular explosion called a supernova.  For this to happen, the mass of the core must be above 1.44 solar masses.

All electrons form neutrons together with protons, and the resulting dead star is made up of neutrons and is called a neutron star.  

Neutron degeneration pressure stops.  However, even if the mass of the core is above 3 solar masses, the neutron degeneration pressure cannot stop and as a result the body becomes a black hole.

A pulsars or neutron star is composed almost entirely of neutrons, although some electrons and protons still remain on the surface.  This compact object is called a neutron star.  

• Neutron star radius is about 10–20 km.  

• The escape velocity of Neutron star can be 100,000 - 150,000 km / s.

• Neutron star is one-third to half the speed of light.  

• The value of g for a neutron star is about 2 × 10111011 or 200 billion times g on Earth.  

The rotation of the neutron star is excessive due to the conservation of angular momentum from the original star.  The currently known fastest rotating neutron star rotates more than 700 times per second!  Due to the magnetic flux, it has an extremely strong magnetic field, which is billion times stronger than that of the Earth.

What happen when two neutron star collide?

Neutron star mergers are rare, requiring systems with two massive stars that have both burst as supernovae.  According to researchers, in any one galaxy, these events occur once every million years.  

Two massive stars are relatively rare compared to low-mass stars on their own.  But when this happens, the two neutrons touch the stars toward each other for millions of years, until they touch and join each other, and in nature's most energetic bursts, a small but powerful force of gamma rays  Receive the beam, which lasts for one or two seconds.  

These tiny GRBs are highly explosive, emitting the same amount of energy in two seconds, as do all the stars of our entire galaxy in one year.  Neutron stars revolve exactly like an intense gravitational atmosphere, where the waves will be strongest.

When two neutron stars merging, there are two possibilities: either they will form a new, larger neutron star together or they will fall into a black hole.

Case 1: Formation of Large Neutron Star

When the neutron star that collides weighs the same solar mass, they form a larger neutron star.  

Both neutron stars have their own gravitational pull and the pulling effect will be the same.  This causes them to merge together and form a new, larger neutron star.

Case 2: Formation of Black Hole

When a mismatched pair of neutron stars that weigh different solar masses, as the stars move toward each other, immense tidal forces break the star's crust and explode into smaller stars, causing  Its hot and dense material begins to erupt and then spirals around the system. 

As the stars merge, the mass mass acquired by the larger star collapses, and a black hole is born.  The upper size limit for neutron stars is 3 solar masses.

Hope you like this article. If you like it please comment and share.

Thankyou,