Star

1. Star

The stars made of hot ball of gases. The stars have colors blue, white, yellow, red and orange. They can be hot or cool. They also can be bright or dim.

2.Types of stars

There are 4 type of stars are white dwarf, main sequence, giant and super giant. They have luminosity, which tells us how much star is dim and bright. And temperature, which tell us how much they hot, and cool.

White drawft are old stars. They have small size. They have hot and medium temperature. There luminosity is dim. There color is blue white. They are in spectral class O. Main sequence are medium stars. They are in medium size. They have hot, medium and cold temperature. They have bright, medium and dim star. They have yellow color. there spectral class are O, B, A, F, G, K, and M. Giants are middle ages stars. They have large size of stars. They have hot, medium and cool star temperature. There luminosity is bright. There color is red and blue white. In spectral class have M. Super giant have middle age. They have large size. They have bright luminosity. There color is red and in spectral class have M.

3.H-R diagram

H -R diagram is stand for hertz sprung Russell and its use for classify stars to their luminosity, temperature, size, and spectral class.

4.Nuclear fusion

stars are made of gas and they look small because they are very far away from us but it is true there are a lot of stars which are more brightest and biggest then the sun. The star heat made in the middle by nuclear fusion. Star have big population with different color, size and temperature. Stars give birth in giant clouds and which called stellar nebula cloud get smaller some time because of the gravity. As they get smaller they become hot and hot. When it is hot a lot, nuclear reaction can start in the center and then the star burn.
   
Star is look a like giant nuclear fire place. The nuclear have 2 famous molecules are hydrogen and helium. They know as nuclear fusion. This is how a star makes their energy.   

5.The life cycle of a star

All stars have different life cycle from other but all of stars made by stellar nebula which mean star give birth or born in big cloud. There are 3 types of stars are sun like star, huge star, and giant star.

Sun like star start in stellar nebula. Then it's become sun like a star start in stellar nebula. Then it's become sun like a star after that they become red giant. Then it's become planetary nebula which means a cloud of dust and gases. Then it finally becomes white dwarf.

Huge star and giant star also created by a stellar nebula. Then they super giant after that they big explosion called supernova after that then huge star become neutron star finally giant star become a black hole (invisible).