Every spectacular shining star as a hub of nuclear reactors has a specific lifespan, forming helium from hydrogen and then to heavier elements carbon, silicon, oxygen, nitrogen and iron. Core temperature gradually increases transforming star into red giant. Rising amount of iron eventually stops the nuclear fusion resulting in the rapid collapse of the core under its own gravitational pull producing shock waves with a massive explosion called supernova, creating nebula which contains heavier elements, ions and stardust clouds. Within every 50 years, a supernova explosion occurs in milky way galaxy.
Cosmologist hunt for supernova by clues left behind through X-rays, gamma rays, radio waves for analysing its chemical composition, temperature, pressure, density and expansion rate. Chinese ancient text first catalogued supernova RCW86 in AD185 as a guest star for eight months and was visible during daytime. Cassiopeia 11,000 light years away, Crab Nebula 6,100 light years away are supernova explosions but farthest explosion observed was SN1987A 160,000 light years away whereas nearest red giant Betelgeuse 640 light years away has chances of being a supernova explosion anytime. There are two types of supernova. Type 1 supernova, have uniform size and releases no hydrogen. Type 2 supernova, releases a large amount of hydrogen and has gigantic size.
According to Chandrashekar limit, after the explosion star with mass 1.3 times mass of sun turns out to be white dwarfs. Star between 1.3-3 times mass of sun ends up as neutron star. Star more than 3 times mass of sun emanate into black holes.
Dense neutron star was first discovered by James Chadwick, ranging from 20-25 km in diameter. Immense gravity combines electron and protons together leaving neutrons behind.
1 teaspoon of neutron star= 100 million tons.
A neutron star is classified into pulsars and magnetars.
Pulsars, rotating neutron stars ejecting beams of electromagnetic radiation from its poles whereas magnetars are rotating neutron stars with extremely influential magnetic field 100 million to 1 quadrillion times stronger than earth. Fritz Zwicky and Walter Baadle were the first to prose this idea. PSRJ1748-2446ad, swiftly spinning pulsar 716 times per second.