Explain the life cycle of a star?

Answer 1

Stars have a typical path of development. The details of this path depend on their mass. Smaller stars, like our sun, will gradually grow hotter, until they become a red giant. Ultimately they will shed their outer layers, and a white dwarf remains. Much more massive stars might go nova in stead.

Answer 2

1.1 Stars are born into a big cloud of dust and gas known as 'nebula', and the bigger its mass the shorter its life cycle. The nebula has hydrogen gas which is pulled by gravity and begins to spin. As the spinning gas gets faster, it heats up and becomes a protostar. Gradually, the temperature reaches up to 15 million degrees thus making nuclear fusion in the cloud's core. The cloud then begins to glow more brightly with little contraction and finally becomes stable. It is now a star and will remain like that, shinning for many years to come.

As the star shines, the hydrogen that is in its core is converted into helium by nuclear fusion. When the hydrogen in the core begins to decrease and the star is no longer generating heat from the nuclear fusion, it causes the core to contract thus becoming unstable which results into the outer shell of the star to start expanding and becoming less bright. As it expands, it cools down and glows a red colour which means that the star has reached the 'red giant' phase and it is red due to it being cooler than the main sequence stage and it is bigger in size due to the outward expansion of its outer shell. In the red giant's core, the helium mixes with the carbon.

As mentioned earlier, stars will eventually collapse and explode though its cycle is determined by its original mass and because of this; they either become a black dwarf, a neutron star, or a black hole.