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Life Cycle of Stars

Life Cycle of Stars

Aren't we mesmerised with the structure of our ever expanding universe? The various components such as galaxies, stars, constellations, planets, satellites and many other celestial bodies form our universe and are observed on day to day basis with the help of telescopes, sent by scientists in space and around the Earth, to know more about them and space.
We live in milky way galaxy which is composed of many stars grouped in spiral form. So, what are these stars actually? Let us dive into this amazing journey of knowing all about stars.

Stars
These are heavenly bodies which have their own heat and light. Infact, these are gigantic spheres of hot gases. A very common star which we all are familiar is Sun. Hydrogen contributes to 72% of the mass of the Sun while helium about 26%. The rest 2% is associated with elements heavier than helium.
But do you know scientists call it an ordinary star even though it appears so large to us than any other star. This is because the Sun is very near to the Earth due to which it appears large to us but there are billion of stars in the sky which have higher or lower mass size and temperature than those of the Sun. Some properties of our ordinary Sun is tabulated below.
 

Mass 2×1030 kg
Radius 695700 km
Surface temperature 5800 K
Temperature at the centre 1.5×107 K
Age 4.5×109 yr

Now, the masses of other stars, bigger and smaller than the Sun, are defined with respect to the mass of the Sun. Thus, mass of the Sun, say Msun, is used as unit of mass.
Masses of other stars lie in the range:
 Msun10Mass of a star100Msun


The above figure compares the size of various stars compared to the Sun. The time elapsed after the formation of a star defines its age. The age of Sun and other stars might be between a few million years to a few billion yea…

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