What's In This Article...
Stars
"We had the sky, up there, all speckled with stars, and we used to lay on our backs and look up at them, and discuss whether they were made, or only just happened."
-- Mark Twain, Huckleberry Finn
A Star is basically a huge and dense ball of various types of gases like H2, He, C, N2, Ne and some other levels of heavier elements that are made inside the core in the later life of a star. As per the official data by researchers about 70 to 80 percent mass of a star is Hydrogen. So it concludes that hydrogen is the main source of fuel for a star.
"Hydrogen is very efficient fuel for stars because it can easily be fused and the energy released is used to run the inner machinery of a star."
Origin Of Stars
Stars take birth where there is enough matter for the formation of a star. When supernova explosions take place somewhere it scatters a very huge amount of matter that includes gases and dust particles in the form of very very huge clouds and this is the perfect place for the birth of a star since it has everything that a star needs i.e a lot of food.
When gases and dust start accumulating to a point due to the action of gravity of concentrated clouds in space then starts a star's birth. This process of accumulation of clouds goes on to some thousands and millions of years that leads in the formation of accretion disk and when enough heat and pressure is generated due to gravity and intense density at the core of the baby star it starts its fusion reactor and suddenly glows up with a bright shine.
A Star follows its main cycle i.e fusion of two elements to form higher elements and radiation of energy and emitting light till its death.
Later by this accretion disk, formation of planets takes place and since they are not very big as the star is, planets can't start fusion in their cores.
One more thing in the formation of a star is being noticed by scientists that it is not possible for a star to take the surrounding matter into it due to its very high angular momentum which opposes the gravity of that unborn star. After a lot of observation scientists come to a conclusion that the massive magnetic field of a protostar may slow down the speed of matter in accretion disk and then the gravity is able to pull the required matter or gas into itself and increases its temp. and pressure so as to start its nuclear reactor at star's core. Hence, magnetic properties also help in the formation of stars.
The formation or birth of our star "Sun" also takes place in the same way. Scientists believe that our solar system and even our sun is also made from the matter exposed from the supernova that results from a Nebula of a star that took place about nearly 5 point something Billion years ago. So we must be thankful to that supernova that had helped in our and Earth's origin. A Nebula is a huge cloud of dust and gas.
Classification Of Stars
Generally we observe in the night sky that stars are of different colors (if you have noticed some appears as a twinkling red, mostly seems to be white, some are also blue and our sun as we can observe it clearly is bright yellowish-orange).
Scientists use different classification measures to categorize stars based on their characteristics, such as spectral class, luminosity class, and temperature class.
- Size.
- Brightness.
- Color.
- Spectral graph analysis.
Evolution Of Stars
Once the main sequence of life i.e nuclear fusion starts inside the core of a star, it becomes a young star from a proto-star. A star continues its 90% of life on its main sequence i.e the fusion chain.
As a star becomes old and older with time its core becomes more and more hot and dense. As the time passes the star faces the lack of nuclear fuel (hydrogen) and due to which nuclear reactions can no longer be possible at the core. Then the gravity dominates and compresses the star even more densely that increases the star's temperature intensely and this thermal energy is used by the outer shell or layer of the dying star and thus the outer shell overcomes the gravity and expands.
The expansion of the outer shell of a star indicates its approaching death and ultimately as a result of expansion the star is converted into a red, called Red Giant.
This is a possibility and speculation that our star (Sun) would be converted into a Red Giant in the next 5 billion years.
Journey of a Red Giant
Once a star is at the extreme position of its Red Giant phase, it either transforms into a White Dwarf Star or a Neutron Star.
Once a star is at the extreme position of its Red Giant phase, it either transforms into a White Dwarf Star or a Neutron Star.
If the initial mass of a star is nearly equal to our sun it evolves as a White Dwarf. A white dwarf has two choices.
Live as a white dwarf and evolve later
At this position the outer layer of Red Giant disappears and only the central core part is left that compresses regularly even more. Due to the further compression, the central part of this star, heat is extremely increased at the central part and even fusion of He atoms starts and this White Dwarf brightens up again. Once all the Helium content of the star is consumed it stops fusion resulting a black dwarf star.
A star can also fuse heavier elements and can produce even more heavier elements but for this the star must be so big and must have enough fuel and extreme condition heat and pressure.
End of life as a Supernova
Chandrasekhar Limit is the maximum mass limit that a White Dwarf Star should have to be stable. It is about 1.4 times the mass of the sun.
If any White Dwarf Star exceeds this limit, it will end its life as the most violent phenomenon i.e a Supernova.
And if the initial mass of the star is extremely more than the sun's mass, it would surely evolve as a Neutron Star.
A Neutron Star is formed from the collapsed core after the supernova explosion (this nova explosion must not be compared with white dwarf as their conditions are different). The matter that Nova or Supernova emits into dark space is used by other stars to be born.
A Neutron Star is named as this since it is made of neutrons only, extremely dense. The life of this type of star is also dependent on its mass, if the mass of a neutron star is too high it would fall into its own gravity and such a high, extreme and intense dense material is a Black Hole. The gravity of black holes is so intense that it curves the space to such a large extent that even light can't escape from it, that's why it's hard to observe a black hole.
"A Black Hole is like a lake of infinite depth in space."
A Pulsar is a type of Neutron Star. The main difference is that a Neutron star does not rotate about its magnetic poles but a Pulsar does, which increases its magnetic field intensity to a very large extent that makes it very dangerous to encounter with Pulsars. They also emit radio waves about their magnetic poles. Their rotation speed is extreme, they can spin many times a second, the fastest record is 716 Hz or 716 spins per second.
Pulsars are the core part of a star and are relatively very small to the size of its original star, hence as per the law i.e. conservation of Angular Momentum, this star can attain such a high angular velocity.
Do you also want to unravel the mysteries of space?
It really is very fascinating that we are able to discover so much about the universe through our telescopes and space probes. But there is still so much more to learn about the universe and we are still very much in the dark. We can’t understand the basic concepts of the universe and black holes, dark matter, higgs boson particle known as god particle, the origin of the universe, and the evolution of stars and galaxies, how supermassive black holes come by and the number of them in the universe, and most important of them all that is the existence of alien species.
Since you came this far, I am sure that you are enjoying reading this article and if you have, then please share this with your friends and family.
0 Comments
Write your queries or share your ideas... just speak up, don't hesitate... ;)