When we look at the night sky, we see uncountable little twinkling dots. These ‘dots’ are called stars. In fact, the Sun is one. In this article, you will learn about the birth, life and death of stars.
Stars have a life that can be compared to a human being’s; they both are born; they both grow and then die.
Some stars have a high mass and some have a low one. Our Sun is an average-sized star. Stephenson 2–18 is a star whose radius is more the 2000 times larger than the Sun’s.
All star formations start with a nebula (an interstellar cloud of dust, Hydrogen, Helium and other ionized gases). Soon, the gases and dust come together forming a protostar surrounded by a protoplanetary disc. Then the Hydrogen in the star starts to fuse into Helium. This is called the main sequence. Both, large and low-medium sized stars have a main sequence. The larger the size of a star is, the shorter its main sequence lasts. The elements in the star keep fusing, until they form iron. The star now has a heavy core. This is why the inner layers collapse, squishing the core and increasing its temperature and the pressure inside it. While the core collapses the outer layers start expanding because Hydrogen still keeps fusing in the outer layers.
Then, the star becomes a red giant or a red supergiant depending on its original size. If it’s a red giant, it begins losing its outer mass as energy or it is lost in the winds. The core remains with a cloud of dust around it. This is called a ‘planetary nebula’. The remaining core is called a white dwarf. If a red supergiant is formed, its gravity takes over leading to it collapsing on itself. This explosion is called a supernova. A high-mass star forms a neutron star (a very dense star) and a very high-mass star forms a black hole, which we are all familiar with.
Our Sun is going to become white dwarf, but don’t worry! This isn’t going to happen soon. It will take about 5 billion years more for it to run out of its fuel, Hydrogen.
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