What is a Neutron Star? Let us put it this way, “It is the living corpse of a dead star”! Sounds weird, right? Don’t worry! We will walk you through the explanation. But before we start with our explanation through 20 interesting Neutron Star facts, we strongly recommend that you read our two earlier posts:
The reason you should read them is that you will get a quick background about the types of stars that lead to the formation of Neutron Stars. So, let us begin.
Interesting Neutron Star Facts: 1-10
1. Neutron stars are formed from stars that has initial mass of at least 8 Solar Masses (M☉) as main sequence stars.
2. Over billions of years, these massive stars burn out their fuel, leaving behind a white dwarf star that features a core rich in iron. At this stage, the electron degeneracy pressure at the core tries to balance out the inward gravitational pull of the dense mass.
3. However, some helium and hydrogen still continue to fuse at the outer layers of the white dwarf and further iron is produced which travels towards the core. This happens over several billions of years.
4. As the iron deposit continues to grow, the electron degeneracy pressure at the core fails to nullify the inward gravitational pull of the accreting mass because of shell burning. As gravitation takes over, the white dwarf starts collapsing on itself.
5. This collapse increases the temperature of the core to about 5×109 Kelvin. At this temperature, high energy gamma rays are produced, which breaks down the iron nuclei into what is known as alpha particles.
6. This is when temperature increases even more and starts fusing protons and electrons of iron atoms into neutrons and in the process, releases neutrinos. This is when the density of the core continues to increase and reaches the figure of 4 x 1017 kg/m3. This actually is the density of the nucleus present in the atom and is known as nuclear density.
7. When the nuclear density is achieved, the gravitational collapse is halted because now, instead of electron degeneracy pressure, the gravitation tug is balanced out by outward pressure of neutron degeneracy.
8. At this stage, the matter that was falling in from the shell of the white dwarf no longer falls in. Rather, in a stellar explosion, the matter is thrown out in space. This is known as supernova explosion.
9. After the supernova explosion which is either Type II or Type Ib, only the very dense core is left behind. This is the Neutron Star.
10. The dense Neutron Star left behind has a number of unusual properties. The most notable of all is its extreme density and miniscule size. When we say miniscule (in context of celestial bodies), we actually mean size smaller than the size New Delhi.