The process of star formation, how stars are formed

How are stars formed?

The basic conditions for the production of stars are hydrogen, gravity, and long time.

Initially, a small piece of hydrogen in the nebula heats up and begins to heat up, causing other substances in the nebula to heat, heat up, and glow. Dust and gas begin to gather under the action of gravity, forming huge whirlpools. In the process of aggregating and compressing the volume, the temperature of the compressed gas increases according to the first law of thermodynamics due to the work done to it by the outside world.

Over hundreds of thousands of years, nebulae will increase in density and form disk-shaped vortices that are larger in diameter than the solar system. And the gas in the center, under the continuous compression of gravity, forms a sphere with ultra-high density and temperature. As the pressure increases, the angular momentum of the vortex material causes a huge column of air to eject from the center, several light-years in diameter, which accelerates the matter over unimaginable distances.

And the core part is the young star.

Over the next few hundred thousand years, young stars will become brighter and hotter by squeezing, reaching temperatures of up to 15 million degrees Celsius. Some gas atoms will fuse at high temperatures to release more energy, and after these fusion reactions, the products will interact with gas, dust, etc. to form clearer spheres, and a star is born.

For tens of thousands, hundreds of millions, even trillions of years to come, it will continue to shine and release energy. The Sun is an ordinary, but important star for us and the entire solar system, which has been providing light and heat for billions of years.

Stars originate from nebulae, which you can compare to gases. For example, the force between gas molecules is usually molecular gravity, but why doesn't gas condense and contract? Because of the irregular movement of gas molecules, the thermal motion and molecular gravity lead to the formation of a homogeneous and stable gas.

If the gas is cooled down to a certain critical value, the gas will liquefy.

Speaking of nebulae, the large ** produces a large number of electrons and protons, which gradually cool down with expansion, so that the electrons and protons combine into hydrogen atoms, which is a primary nebula. Primary nebulae rely on the balance of gravitational attraction and thermal motion to achieve uniform stability, with the expansion of the universe, the temperature of the nebula gradually decreases, so that the internal balance is destroyed, the production of micro-clusters, and will attract more matter, gravitational potential energy into internal heat energy, when the mass reaches a certain critical value, the internal temperature of the star will be very high, thus igniting thermonuclear reactions, and finally forming stars. The nuclear fuel of a star is hydrogen, and when hydrogen fusion is complete, the converted helium will fuse into carbon, and eventually accompanied by a series of fusions, nuclear reactions will occur in turn, and finally fusion into iron.

Then if the mass is too small, it will evolve into a white dwarf, and if the mass is larger, it will produce a supernova explosion, and the material that bursts out will form a secondary nebula, which contains elements such as C, H, O, N, etc., which are the materials that make up the earth and terrestrial planets, and the secondary nebula will produce new stars and planets, and the original star core after the explosion will form neutron stars, and if the mass of the original star is large enough, it will form a black hole.

Nebulae are the materials that make up stars, but the mass of the matter that really makes up stars is very large, and a nebula cluster with a radius of 90 billion kilometers is required to make up a star like the Sun. The process of clustering from nebulae to stars can be divided into fast contraction phase and slow contraction phase. The former lasted hundreds of thousands of years, and the latter lasted tens of millions of years.

After the nebula shrinks rapidly, the radius is only one percent of the original, and the average density increases by 100 million billion times, and finally forms a "star embryo". It is a thick, dark cloud with a dense nucleus in the center. After that, it enters a slow contraction, also known as the protosidereal phase.

At this time, the temperature of the star embryo continues to rise, and when the temperature rises to a certain extent, it will shimmer and glow to show its existence and enter the juvenile stage of the star. However, the star was still unstable and was still surrounded by diffuse nebulous material that projected material into the world.

Portrait of a star.

In the silent night sky, people see that the stars in the sky are all shining, and there is no difference except for size and light and darkness. Is that actually the case? Of course not, each star has its own unique physiognomy. Back in the Han Dynasty in China, we.

Our wise ancestors, through careful observation, have divided the stars into five colors: white, red, yellow, pale, and black. In 1665, Newton of England discovered the continuous spectrum of the sun using a prism, and thus knew that daylight was made up of a mixture of various colors of light such as red, orange, yellow, green, blue, indigo, and violet.

The "key" to unlock the mysteries of stellar physiognomy

In 1814, the German Francometer and the fee spectrometer were used to study the solar spectrum.

Investigate. They made a slit in the shutter of the darkroom so that sunlight could shine through the slit onto a prism behind which was a small telescope. Through the small telescope, Fu Lang and Fei were surprised to find that many dark lines appeared in the spectrum of the sun's "seven color bands".

After repeated counting, there are as many as 567 such dark lines. Based on several discoveries made by previous people, we have come to understand the true portrait of the star. The difference in the color of the star indicates that the temperature of each star is different, such as the white temperature is high and the red temperature is low, so the spectrum is the "key" to understanding the star.