Why is it important to survive the white dwarf phase during the stellar transition?

Around the core of the burned star (white dwarf), there is a ring of debris and dust particles around. When stars the size of the Sun expand and eventually become white dwarfs, their planets are likely to be removed from the system or even consumed. Scientists have explored and found that if a planet has the dual properties of being strong and of lower mass.

Then, when its home star dies, it is still possible to survive the wave of tugboats generated by its parent star.

The research team outlined a computational procedure for the tidal forces between a near-spherical solid planet and a white dwarf, as well as the type of corpse left behind by a smaller star like the Sun. Scientists use the difference in gravitational strength between two points, such as stars and planets, or the Earth and the Moon, as tidal forces between them. As the tidal forces change (because the gravitational influence of one of them changes), some companions will get better, but others will fall apart.

At this stage, all exoplanets discovered by scientists are orbiting a star that will become a white dwarf. In the process of stellar conversion, the research team also inserted a variety of possible factors, such as their shear viscosity (their resistance to deformation or flow) and rotation rate, in order to get a clearer picture of some process behaviors

The stars in the sky may seem eternal, but eventually most of them will turn into white dwarfs, the last observable evolutionary stage of low- and medium-mass stars whose faint star corpses dot the Milky Way. The main sequence of stars, including the Sun, is formed by gravitationally attracted clouds of dust and gas. How stars evolve over their lifetime depends on their mass.

Many white dwarfs fade away, eventually emitting all their energy and becoming so-called black dwarfs, but those stars that share a system with their companions may have a different fate.

If a white dwarf is part of a binary system, it may pull matter from its companion star onto its surface. Increasing the mass of a white dwarf can give you some interesting results. At other times, a white dwarf can pull enough material out of its companions, and in a nova, it's a much smaller one.

Since the white dwarf remains intact, it can repeat the process many times when it reaches a tipping point, absorbing life back into the dying star again and again.

Scientists say the planet's survival in the white dwarf phase is so important that observable debris or waste and asteroids can be introduced into the white dwarf's atmosphere, even if the planet itself is outside the narrow detectable range. In other words, when the Sun reaches the end of its life, the relatively small body of the Earth will play an important role in the fate of the Moon.

Exoplanets are orbiting a star that is about to become a white dwarf.

Because this is the most important period of stellar transition.

Because this is a relatively important period, it is very important.

Because he can observe small things.

Then this stage is a life-and-death stage, and if something goes wrong at this stage, it is possible that the conversion will fail.

A white dwarf (also known as a degenerate dwarf) is a low-luminosity, high-density, high-temperature star. Because of its white color and relatively small size, it was named a white dwarf. White dwarfs are end-of-evolution stars that are mostly made of carbon and covered with a layer of hydrogen and helium.

White dwarfs have cooled and darkened over hundreds of millions of years, they are small in size and low in brightness, but they are dense and massive. The Catalog of White Dwarfs, published in 1982, showed that there were 488 white dwarfs in the Milky Way, all of which were near the Sun. According to the statistics of observational data, about 3 stars are white dwarfs, but theoretical analysis and estimation suggest that white dwarfs should account for about 10 of all stars.

White dwarfs are formed at very high temperatures, but because there is no energy for **. As a result, it will gradually release its heat and gradually become cold (lower temperature), which means that its radiation will gradually decrease from the initial high color temperature and turn red over time. Over a long period of time, the temperature of the white dwarf will cool to the point where the luminosity is no longer visible, and it will become a cold black dwarf.

However, the universe is still too young (about 13.7 billion years old) to radiate thousands of kilobytes of temperature even from the oldest white dwarfs.

You're getting a concept wrong. A white dwarf is the core of the original star, and its temperature actually represents the temperature of the star's core after the outer cryogenic gas disappears. And it turns out that the temperature of a star is its surface temperature.

Stars produce energy through nuclear fusion reactions. Nuclear fusion reactions always occur at or near the inner core of a star. The outer gas of the star only acts as a conductor of energy, and the red-hot gas in the outer layer of the star is heated by the energy generated in the inner core.

The temperature of the core of the star in the main sequence stage will not be lower than 12 million degrees, otherwise there will be no nuclear fusion reaction, for example, the central temperature of the sun is about 15 million degrees. The temperature distribution in a star is that the further out the layer, the lower the temperature, so that to the surface of the star, the temperature is only a few thousand degrees.

The white dwarf no longer produces energy, the energy it emits is all accumulated during the nuclear reaction phase, and its surface temperature will drop over time until it becomes a black dwarf that no longer emits light. The white white dwarf we see must still be in the hot stage, otherwise it would not have been spotted because it is too small to be seen without emitting strong light. So it must still be in the high temperature stage.

As a result, its temperature must be many times higher than the surface temperature of the original star.

This possibility is still possible, but it is relatively unlikely.

White dwarfs are formed from stars. When the star runs out of energy, it collapses under its own gravitational pull, and if the mass is large enough, it will collapse into a black hole, while the star with less mass will usually collapse into a white dwarf after the energy is exhausted and dies.

Although a white dwarf is formed from a star that has run out of energy, it is not a dead star in the true sense of the word. Although the light of the white dwarf star is very dim, it is still a hot planet, and it is still releasing heat to the surroundings, and this heat is not very low, but not as strong as the sun. Some white dwarfs can even continue to release heat for billions of years.

White dwarfs cool down very quickly in the early stages of formation, but after 4 billion years they become very stable, and the cooling becomes very slow. At this stage, as long as the planet is just the right distance from the white dwarf, it will get a temperature that is perfect for the birth of life. Moreover, white dwarfs will exist for tens of billions of years, and in such a long time, it is possible for those planets that happen to be in the habitable zone to give birth to life, but this probability is much smaller.

But the universe is so big, how many white dwarfs will exist, maybe in some places in the universe, there are some planets with bad luck, there are all kinds of creatures living on them, maybe there are civilizations.

The white sail destroys the dwarf star and accounts for the total number of pure stars in the Milky Way ().

a.1 in 10,000.

b.Thousandth.

c..Per cent.

d.Tenth.

Correct answer: c

A white dwarf is a low-luminosity, high-density, high-temperature star. Because of its white color and small size, it is called a white dwarf.

When the outer gas ejected by the alien becomes a planetary nebula, its inner core develops into a hot, dense star. These stars have a high surface temperature and emit strong ultraviolet light with blue-white light; Its radius is small, about the same as the radius of the Earth. However, due to their high temperature, they are sometimes brighter than the sun.

Many people refer to these stars as "white dwarfs", which is not accurate. This is because the "white" in "white dwarf" means white and "short" means low brightness. Although the color of the objects in the planetary nebula is white, its brightness is not lower than that of the Sun.

Introduction to major white dwarfs:

1. Sirius B

The closest white dwarf to Earth is the companion star of Sirius B, which is only light-years from Earth. Sirius, located in the constellation Canis Major, is the brightest star in the night sky. The mass of Sirius b is the mass of the Sun, with a radius of only 6,000 kilometers, which is smaller than the radius of the Earth.

2、stein2051b

Stein2051b is another well-known close-up white dwarf star, located just 17 light-years from Earth, forming a pair of binary stars with a red dwarf star numbered Stein2051a. A portion of the starlight emitted by a distant star passes near the white dwarf star and eventually reaches Earth.

Between October 2013 and October 2015, astronomers used Hubble's WFC3 to measure the mass of white dwarfs by taking multiple photographs of the positions of distant stars and determining how "bent" each star was.

3. Other white dwarfs

Using Hubble's observations, astronomers have discovered a large number of white dwarfs in globular clusters, in addition to white dwarfs in single and binary star systems. For example, Hubble's ACS captured the globular cluster NGC6397, which is located 7,000 light-years away in the constellation Tiantan, 7,000 light-years away from Earth, and contains hundreds of thousands of stars. From images from ACS, astronomers confirmed 84 white dwarfs.

The above content reference: Encyclopedia - White Dwarf.