Stars and Their Types

The heavenly bodies that twinkle are called stars. The thousands of twinkling stars that we observe in the clear night sky are part of our Milky Way. At night, about 4000 stars are visible to the naked eye, including the Sun, which is an ordinary star.

• Stars are massive spheres of hot gases, mostly made of hydrogen and helium. Stars have their own light. Stars are huge, glowing balls of gas that shine in the night sky. The sun is also a star.
• The Sun appears larger because it is closer to Earth, but many stars are bigger or hotter than the Sun.
• Some of the stars that we see are bright, whereas others are faint. Stars radiating different colours such as blue, white, yellow, and reddish can be seen in the sky. We also see stars with varying brightness (luminance).
• The birthplace of stars is the huge nebulae, made of dust particles and gases. Stars vary widely in mass, size, and temperature, forming a diverse range of celestial bodies in the universe.
• Generally, the surface temperature of stars ranges from 3500°C to 50000°C. The colour of stars changes according to their temperature.

1. Nebula (birthplace of stars): A nebula is a large cloud of hydrogen gas and dust. Gravity pulls the particles together, forming a dense, hot sphere at the centre, creating a new star.
2. Ordinary Star/Massive Star: Stars can either be small or massive, depending on how much matter they have. Our Sun is an example of an ordinary star.
3. Red Giant/Red Super Giant: After using most of their fuel, stars expand into red giants or red supergiants, depending on their size.
4. Planetary Nebula/Supernova: Small stars like the Sun turn into planetary nebulae, releasing outer layers of gas. Massive stars explode as supernovae, releasing a huge amount of energy.
5. Final Stage: Ordinary stars shrink into small, dense white dwarfs after the planetary nebula fades.

Massive stars can either

Collapse into an extremely dense neutron star. If very large, they form a black hole, where gravity is so strong that even light can't escape. This entire process takes millions to billions of years. Each stage of a star's life depends on how massive it was at birth.