Unknown Facts Of Stars:Stars Are Born From Huge Clouds Of Dust.

Stars

Stars are extremely large gaseous bodies found in the universe. They produce enormous amounts of light and other forms of energy through nuclear fusion. The Sun Is the star closest to the Earth.

Stars vary in their shape and size. Some such as neutron stars have a radius of only about it) km, while some such as the Pistol Star are 100 times bigger than the Sun.

Life cycle

Stars are born from huge clouds of dust, hydrogen, helium, and traces of other heavier , elements. All stars begin their life as protostars, Which are formed when the huge clouds of dust, hydrogen, helium, etc. ,collapse under gravitational forces. As the gravitational attraction between the atoms increases, it adds more atoms to the centre of the protostar. This p‘rocess'of adding atoms is called accretion. Numerous reactions occur inside protostars, which make them very unstable. They only attain equilibrium when gas pressure equals gravity. Once a protostar attains equilibrium and the critical temperature is reached, nuclear fusion begins and the star begins to radiate energy into space. During this phase, a star is called a main sequence star. After all the hydrogen present in a star has been fused to helium, the star begins to burn helium to maintain its equilibrium.While helium burns in the core, hydrogen rapidly burns out in the shell of the star. This increases the temperature in the outer shell and it expands. At this point a star is known as a red giant. Gradually, the star loses its brightness and turns into a white dwarf and ends its life as a black dwarf. But not all stars die in this same way. Some stars do not turn into red giantsflhey become white dwarfs and end their lives as black dwarfs. Some stars end their lives in a huge explosion called supernova.

Variable stars

Some stars keep on changing their brightness. Such stars are known as variable stars. There are two types of variable stars: intrinsic variable stars and extrinsic variable stars. Intrinsic variable stars change in brightness because of the change in their physical properties. Extrinsic variable stars change in brightness because of external properties, such as rotation or eclipses.

Black hole

A black hole is the remnant of a super collapsed star. Black holes have a very strong gravitational pull and they suck everything including light, into them. They are the evolutionary endpoints of stars at least 10 to 15 times as massive as the Sun. These stars collapse to the point of Zero volume ~ and no gravity. Because no light escapes the star,it is called a black hole.

White dwarfs

White dwarfs are dying stars that emit a White glow. Most white dwarfs are formed after a red giant has burned all its original hydrogen and helium. Such stars expel most of their outer material creating a planetary nebula. The hot core
keeps glowing until it cools down, which takes almost takes a billion years or so.

 Binary stars

Binary stars are a pair of stars that move around a common centre of mass.They are also known as double stars. There are two types of binary star systems, visual and spectroscopic. A visual binary system consists of stars that are visible through a telescope. Spectroscopic system consists of stars that look like a single stars that Star through a telescope as they are very close to each other. Algol and Sirius are example of binary stars.

Neutron star

Neutron stars are very dense stars composed of neutrons.They are about 19.3 km in diameter. Neutron stars are the endpoints stars, which are four to eight times as massive as the Sun. When these huge stars finish burning their nuclear fuel, they undergo a supernova explosion.This explosion blows off the outer layers of the star and the central region collapses under gravity. As it collapses, the protons and electrons in the region combine to form neutrons.

Supernova explosion

When an old massive star exhausts its fuel, it explodes. This is called a supernova explosion.It is one of the most energetic explosive events in the universe.