1. What is a star?
Stars are large hot gases ball some of are dim and some are bright. The stars look small because the star far away from us. But actually they look big. Some star are bigger then sun. stars have different color and sizes.
In the center of the star is nuclear fusion. Is where the heat is made. Star can classified in different type. Like color, sizes, luminosity, temperature etc.
2. Type of stars
Stars are classified into different types. They are super giant , giant , main sequence and white dwarf. Also the stars classified into other different categories. Such as types of stars. color, luminosity,age ,sizes, special class and temperature.
White dwarf are old stars and dim. They color are white. The temperature between 4,000-7,000
,spectral class of white dwarf can be B, A, F. Main sequence stars are young medium stars that can be any colors, They have different luminosity and temperature. They all have different special class. Super giant stars are super huge middle age stars, that can have any color, temperature luminosity and spectral class.
3.H-R Diagram
H-R Diagram is a graphical tool to show the characteristics of stars. and classified them based on the luminosity, color, sizes. based on all the information about stars. also can define the special class.
4. Nuclear Fusion
The star is born with a giant cloud the cloud gets smaller because the gravity. When it shrink it gets hotter and hotter. When it is hot enough, the star is born. This is nuclear reaction. Nuclear fusion help stars to make enery /it is the process of the nuclear reaction change two hydrogen molecules into a helium molecule. and enery inside the stars.
5.The life cycle of a Star
Star have a life cycle. it has the process. Every stars are born with giant clouds with dust and gas. This is called stellar nebula. But there is a different cycle between sun-like, huge stars and giant stars.
Sun-like stars born with stellar nebula which is a giant cloud with dust and gas, and then it forms a star, next step will become a red giant star, and the red giant star will collapse in to a cloud of dust and gas, this is planetary nebula, and it will become a white dwarf after it, and finally it die and become a black dwarf. Huge star born with stellar nebula too, after it forms a star, it become a red giant, the star will have a big explosion called supernova, and it become a neutron star. Giant star follow almost the exact steps as the huge stars, but unlike huge star, after the supernova, giant star will become a black hole.
