Our universe is vast, incomprehensible beyond our understanding and unexplored. There are so many galaxies, planets and stars that it would take us several light years to discover even a quarter of the universe in which we live.
Speaking of stars, there is a famous saying that there are more stars in the universe than grains of sand on all the beaches on earth combined. This is a staggering figure that cannot be quantified.
In this article we will learn about the stars. How are they born? What are they made of? How do they die? And what happens after his death?
We’ve all looked at the night sky and counted the number of stars (and haven’t) and pondered the question: Are stars just bright points of light in space? Or are they something much bigger?
The answer is that they are much larger than we can imagine.
But what exactly are stars?
Stars are huge luminous balls of gas held together by their own gravity. They are composed mainly of hydrogen and helium, two elements that make up almost 99% of the universe.
The best known star to us is the Sun.
It is the closest star to Earth, so close that it takes approximately eight minutes for sunlight to reach us.
Read also | List of known galaxies in the universe
How are stars born?
Stars are born within clouds of dust. When there is instability in the depth of these clouds, accumulations with enough mass are created so that the gas and dust begin to collapse under their own gravitational pull.
The elements that make up the core of the cloud begin to heat up as the cloud breaks up. This heated core at the center of the collapsing cloud is known as a protostar.
When the cloud breaks up, its dense, heated core begins to accumulate gases and particles. When their hydrogen nuclei fuse with helium nuclei, the formation of a star begins.
This protostar then becomes a star.
Read also | The most powerful explosion in the universe detected by NASA sent shock waves to Earth.
How many types of stars are there?
Based on temperature, stars are mainly classified into 7 spectral types.
They are:
- Or (↑ temperature)
- b
- TO
- F
- GRAM
- k
- M (↓ temperature)
Class O is the hottest type of star, burning at more than 40,000 K, and M is the least hot star. One important thing to keep in mind is that the hotter the star, the less life it has.
So, class O has the shortest life and class M has the longest life.
Source: astrobackyard.com
Other notable types of stars include:
- Red dwarfs: They are the smallest, coldest, and by far the most common type of star in the Milky Way.
Proxima Centauri is the closest red dwarf to the Sun.
- Yellow dwarfs: A yellow dwarf is a star with a spectral class of G that is located on the main sequence. Yellow dwarfs represent about 10% of all stars in the Milky Way. They glow a dazzling yellow color (hence the name) and have a surface temperature of approximately 6000°C.
An example of a yellow dwarf or G-type star is the Sun.
- Supergiant stars: Supergiant stars are the largest stars in the known universe. When a star runs out of hydrogen and begins burning helium, its core collapses and its outer layers expand, eventually becoming a supergiant star.
An example of a red supergiant star is Herschel’s Garnet star in Cepheus.
- Neutron stars: Neutron stars are created when the cores of massive stars collapse after running out of fuel. These types of stars do not actively generate heat.
PSR J0108-1431 in the constellation Cetus, located 424 light years from Earth, is an example of a neutron star.
- White dwarfs: When a low-mass star has used up all its nuclear fuel in the center and has lost its outer layers as a planetary nebula, a white dwarf forms.
Located 8.6 light years from Earth, Sirius B is the best-known example of a white dwarf.
- Black dwarfs: are a theoretical type of star, said to form after a white dwarf star runs out of heat and turns into a cold, solid, dense mass.
- Brown dwarfs: They are also classified as failed stars since they fail to generate the heat necessary for hydrogen fusion because they are too small.
Gliese 229B is an example of a brown dwarf.
How do stars die?
Like everything else in the universe, stars also have a lifespan. The life of a star depends on its mass, that is, the larger the star, the shorter its life.
When a star’s nuclear fuel runs out, it will collapse under the force of gravity.
Source: Britannica.com
What happens after stars die?
What happens after a star dies depends on its mass.
In the event of the death of a small star like the Sun or a medium-sized star, a little larger than the Sun, it expands until it becomes a red dwarf, which little by little loses its helium, becoming a white dwarf. eventually becoming a black dwarf. .
When a massive star dies, it consumes its fuel, which is hot enough to fuse heavy elements like helium and carbon. When there is no fuel left to use, the outer layers of the star explode violently. This explosion is known as a “supernova.”
The remains of a supernova explosion are a “neutron star,” which is the collapsed core of the star.
Or if there is more mass, it will give rise to a black hole, the densest object in the entire known universe.
We hope we have been able to quench your thirst for knowledge about stars, their birth, formation, types and death.
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Categories: Optical Illusion
Source: ptivs2.edu.vn