Does anyone know how stars and planets evolve? beginning, middle age, old age .

The star begins as a cloud-like gas and slowly begins to shrink into a sphere. Gradually it began to heat up, and in middle age it began to fuse and glow. The energy of later years is re-fused by helium produced by fusion in middle age, which emits light and heats, and gradually becomes larger, and the last supernova with a small mass explodes, and the last massive ones evolve into white dwarfs or neutron stars or black holes.

Due to the large size of the universe, nebulae are formed, and the large gas clouds collapse due to the instability of the gravitational pull of the macro-stove itself, and the stars enter the formation stage, and under the influence of gravity, the planets surround the stars.

Stars and planets are formed by some chemical elements, over thousands of years, tens of thousands of years.

In general, there are many factors for the formation of stars and planets, maybe it is a combination of factors in nature that will cause the two of them to travel, maybe he has always had the cherry blossoms.

What books have you read that make such a point....The common saying is that the formation of white dwarf neutron magnitude, and finally become a black hole, how can it be a planet? The planets around him, etc., could be swallowed by the black holes that formed.

(1) It will not become a planet. Objects with masses less than 20 times the mass of the Sun will become white dwarfs, brown dwarfs, neutron stars, and then further evolve into black dwarfs or objects similar to black dwarfs. Those with more than 20 times the mass of the sun will become black holes or giant magnetars, and it is unknown what the giant magnetars will evolve into, because we don't know much about magnetars, and they may evolve into legendary quark stars.

As for the black hole will evolve into a white hole, but we will have to wait for the day when it **. The lifespan of dead objects of stars is quite long, such as black dwarfs and black holes, which are much longer than the universe.

2) The star is too old to have a thermonuclear reaction, but its mass is still partial, so the planet will still move around it, but the orbit will become larger and the period will be longer.

3) Planets and dead stars are unlikely to be captured by other stars, because the distance between stars is very far, and other stars are not capable of doing so, unless it is a black hole that is close to the star.

The evolution of stars.

1.Formation of stars.

At a certain point in the development of the universe, the universe is filled with uniform clouds of neutral atomic gas, and the large gas clouds are unstable due to their own gravitational attraction and collapse. In this way, the star enters the formation phase. At the beginning of the collapse, the pressure inside the gas cloud is very small, and the matter accelerates to the center under the action of gravity.

On the one hand, the density of the gas has increased dramatically, on the other hand, due to the conversion of the lost gravitational potential energy into heat energy, the temperature of the gas has also increased greatly, and the pressure of the gas is proportional to the product of its density and temperature, so that in the process of collapse, the pressure increases faster, so that a pressure field sufficient to compete with the gravitational force is quickly formed inside the gas, and this pressure field finally stops the gravitational collapse, thus establishing a new mechanical equilibrium shape, called the star billet.

2.The stable period of a star – main-sequence star.

During the contraction process, the density of the main sequence star increases, and a part of the shrinking air cloud reaches the critical point under the new conditions, and a small perturbation can cause a new local collapse. Under certain conditions, the large gas cloud shrinks into a condensate and becomes a protostar, and the protostar continues to shrink after adsorbing the surrounding gas cloud, the surface temperature remains unchanged, and the core temperature continues to rise, causing various nuclear reactions in temperature, density and gas composition. The heat energy generated makes the temperature rise extremely high, and the gas pressure resists gravity to stabilize the protostar and become a star, and the evolution of the star begins with the main sequence star.

3.The old age of the stars.

Since the main component of star formation is hydrogen, and the ignition temperature of hydrogen is lower than that of other elements, the first stage of stellar evolution is always the combustion phase of hydrogen, that is, the main sequence stage. During the main sequence phase, a steady balance of pressure and surface temperature distribution is maintained inside the star, so that its luminosity and surface temperature change only slightly throughout the long phase. Let's discuss how the star will evolve further after the hydrogen in the core of the star is burned.

The product of helium combustion is carbon, after helium extinguishment, the star will have a helium shell in the core area of carbon, because the remaining mass is too small to reach the ignition temperature of carbon, so he ends the evolution of helium combustion and goes to thermal death.

4.The endgame of the stars.

Throw away some or most of its mass and become a white dwarf. Stars above 8 10m will eventually become neutron stars or black holes by the gravitational collapse of the star's core.

1. Stars will evolve into red giants in middle age, red giants are a shorter unstable phase experienced by stars in the later stages of burning, which lasts only millions of years depending on the mass of the star, which is very short compared with the stable period of billions or even tens of billions of years of stars.

2. Stars are spherical luminous plasmas condensed by gravity, and the Sun is the closest star to the Earth. Almost all of his stars that can be seen at night when the Earth grinds are in the Milky Way, but due to their distance, they seem to be just fixed points of light.

Stars are still normal stars in middle age and are called "main-sequence stars".

From the moment a star is born, it appears on the main sequence of the Hérau diagram and becomes a main sequence star. It then slowly moves upwards on the main sequence, slowly increasing in volume and luminosity, and slowly decreasing in surface temperature.

More than 90% of a star's life is in the main sequence until old age.

When the star reaches old age, it quickly leaves the main sequence and moves vertically upwards in the Herrault diagram into the red giant region in the upper right. At this point, it expands into a red giant or red supergiant.

Therefore, the star is still a normal star in middle age compared to young age.

The Sun is currently in middle age and is a normal main-sequence star.

Harrowtu.

There are many stars in the cosmic environment as we know it at present, and it is one of the largest groups in the universe, which is also quite concerned by scientists. Among the stars, there are neutron stars, white dwarfs, and so on. And that's not what we're going to talk about today, it's black dwarfs!