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Which star is cooler? Why are stars colored? Hot and cold stars

"Cold Sun with a hot photosphere

The mechanism of gravity"

All peoples, at all times, have turned with gratitude to the Sun - the eternal free giver of warmth and light. Great M.V. Lomonosov, speaking about the Sun, called it “an eternally burning Ocean - fiery whirlwinds spin there...”. But how does this Sun work? Due to what, billions of years ago, such colossal energy is created by a star around which the eternal cold of the Universe is? Moreover, there are billions of stars in our Galaxy alone, and there are billions of galaxies in the Universe.

It is known that 450 years ago the great astronomer and physicist Johannes Kepler believed that “stars are frozen into a motionless solid of ice”! The famous astronomer and scientist W. Herschel (1738 - 1822) in 1795 created a theory of the structure of the Sun, which was widely accepted for more than a century. According to this theory, “the Sun itself is a cold, solid, dark body, surrounded by two cloud layers, of which, the photosphere, is extremely hot and bright. The inner layer of clouds, like a kind of screen, protects the central core from the effects of heat.” The theory of a cold Sun with a hot photosphere could later be successfully developed and gradually established through subsequent indisputable evidence and discoveries.

And one of the first to take a step in this direction was D.I. Mendeleev. In his work (“An Attempt at a Chemical Understanding of the World Ether,” 1905), he reported: “The problem of gravitation and the problems of all energy cannot be imagined to be really solved without a real understanding of the ether as a world medium that transmits energy over distances. A real understanding of the ether cannot be achieved by ignoring its chemistry and not considering it an elementary substance.” “The element “y” (Coronius), however, is necessary in order to mentally get close to that most important, and therefore most rapidly moving element “x”, which can be considered the ether. I would like to tentatively call it “Newtonium” - in honor of Newton...”

In the journal “Fundamentals of Chemistry. (VIII edition, St. Petersburg, 1906) D.I. Mendeleev (1834 - 1907) publishes his outstanding table: “The periodic table of elements by groups and series.” Taking into account the fundamentalism of the microparticles of the “world ether” in the construction of the elements of matter, Mendeleev introduced into his table in the zero group two microparticles of the “world ether” that fill the entire interstellar space, Coronium and Newtonium, which are directly involved in the processes of creating the elements of matter and in fulfilling the “task of gravity” " But after the death of D.I. Mendeleev's fundamental microparticles Coronium and Newtonium were removed from the table. Thus, the connection between the subtlest microcosm of interstellar space and the surrounding macrocosm, created from the elements of matter, was lost. “If the temperature of a system in equilibrium changes, then, as the temperature increases, the equilibrium shifts towards the process that involves the absorption of heat, and when the temperature decreases, towards the process that occurs with the release of heat.”

According to van't Hoff's law (1852 - 1911): because The Sun releases heat on the surface T = 6000K, then inside the Sun there must be a process of decreasing temperature. Therefore, there is cold inside the Sun! In the 1895s, Van't Hoff's law of equilibrium under temperature changes was formulated:

In the first decades of the twentieth century, through the works of outstanding scientists, the constituent parts of the atom were discovered: electron, proton, neutron. But for the scientific world, the question of the mysterious source of energy from the Sun still remained unclear. In the 1920s, nuclear physics was still young, taking only its first timid steps. And then the English astronomer Arthur Eddington (A.S. Eddington) (1882 - 1944) proposed a model: the Sun is a gas ball, where the temperature in the center is so high that due to the released nuclear energy, the glow of the Sun is ensured. In a thermonuclear reaction, four protons (hydrogen nuclei) combine to form the nucleus of a helium atom, releasing thermal energy. The nucleus of a helium atom is known to consist of two protons and two neutrons. Atomic physicists objected to Eddington's hypothesis because It is very difficult to combine hydrogen nuclei, because These are positively charged protons that repel each other. In the 1920s, this problem was intractable, but decades later, with the discovery of the strong nuclear force, it was believed that the difficulties could be overcome. If protons are collided at high speeds, they can become so close that strong nuclear force is possible and, despite electrostatic repulsion, the protons will form a helium nucleus. The temperature at the center of the Sun is 15 mil. degrees is high enough for hydrogen nuclei to reach high speeds at which their fusion is possible, as Eddington argued.

Almost a century has passed, billions of dollars in foreign currency have been spent, but it has not been possible to create an earthly reactor where the synthesis of hydrogen nuclei into a helium nucleus should occur at high temperatures. The main reason is ignoring thermodynamic processes in the surrounding nature, where the cold thermonuclear process is continuously going on.

It is necessary to return to the theory of V. Herschel - “a cold Sun with a hot photosphere”, to Van’t Hoff’s law of temperature equilibrium, to microparticles of interstellar space predicted by D.I. Mendeleev, - Coronium and Newtonium, participating in the creation of atoms of the elements of matter. The interstellar space of the Galaxy, which is an equilibrium temperature system with a temperature TR = 2.7 K, is filled with billions of hot stars that revolve around the center of the Galaxy. This means that there is a sharp temperature difference in the Galaxy - and this creates a force for the transition of microparticles of interstellar space to the center of cold; movement, compression of microparticles and temperature increase. Formation of protons, atoms of elements of matter, stars from microparticles. The Sun, like any star, is an ideal heat engine, continuously radiating heat into the interstellar space of the Galaxy. But the temperature of interstellar space TR = 2.7 K is constant. Consequently, the amount of heat the Sun gives off to cold interstellar space is the same amount of heat the Sun receives into its refrigerator from interstellar space. This entire closed cycle of the thermal process follows the second law of thermodynamics - the transition of heat to the cold region. The temperature regime of the Sun follows the operation scheme of a refrigerator: the ratio of the surface temperature of the Sun Tss = 6000K to the temperature of the Solar system Tss, where solar plasma is ejected, must be equal to the ratio of the temperatures of the Solar system Tss to the temperature of interstellar space TR = 2.7 K, where, in Ultimately, the sun's heat is rejected.

We get the formula: Tps / Tss, = Tss / TR; T 2ss = Tps TR; Temperature of the Solar System: Tss = 127.28K

Since the Sun is an emitter of heat through the photosphere, then it must have a refrigerator with a temperature Txc in the center, since the Sun cannot emit heat without constant replenishment of heat - cosmic temperature particles, which must continuously enter the refrigerator of the center of the Sun's core.

Using a formula that takes the form: Tcc / T R = T R / Txc, you can determine Txc - the temperature of the refrigerator in the center of the Sun, which makes it possible to use the reverse thermal process: how much heat the Sun gives off in TR = 2.7 K - into the interstellar space of the Galaxy through the temperature output field Tcc = 127.28 K, this is how much heat the Sun should receive into the refrigerator Tcc from interstellar space. We determine the temperature of the refrigerator in the center of the Sun: Txc = TR 2 / Tcc Txc = (2.7K) 2 / 127.28K = 0.057275K = ~ 0.05728K

The temperature input of space heat into the cold center of the Sun and the temperature output of heat from the surface of the Sun into outer space, through the output temperature field Tcc = 127.28 K, are presented in the diagram:

In the refrigerator, microparticles T = 2.7 K break into microparticles with a temperature equal to microparticles of the refrigerator T = 0.05727 K with heat absorption. The pressure in the refrigerator increases and “extra” microparticles are thrown out of the refrigerator and become the basis of the refrigerator particle, which, with the help of cosmic microparticles, increases its mass to a proton, neutron, atom in the graphite tunnels of the inner, central, and outer cores of the Sun. Without a cold center in a particle, the creation, formation of a proton, an atom, a cell is not possible. Thus, a cold thermonuclear process occurs inside the Sun.

Nature creates structures of the same type: life in a cell and a particle begins with microparticles. An atom of a substance appears; the process of creating an atom occurs without increasing the temperature due to the entry of cosmic microparticles into the particle refrigerator.

The release of solar energy comes through a proton shock wave. The inner core has a proton shock wave temperature T = 2.7 K; central core - T = 127.28K; outer core - T = 6000K.

According to the formula for the equality of the macro and microworlds, Mvn = mрСk, where M is the mass of the proton shock wave of the Sun;

v is the speed of a proton in a proton shock wave with a temperature T = 6000K. n = g = 47.14 m/s2 - acceleration of the ejection of particles from the proton shock wave; mр - proton mass;

k = S/sp - coefficient of ratio: the area of ​​the sphere of the proton shock wave of the Sun S = 4 π R2 to the area of ​​the proton sp = π r2.

We determine the radius of the proton shock wave: R = 6.89.108m.

Since a proton shock wave with a temperature T = 6000K is created at the surface of the outer core, therefore, the radius of the core is actually equal to the radius of the proton shock wave. The volume of the outer core according to the proton shock wave is equal to V = 13.7 .1026 m3

The radius of the Sun was determined from the photosphere and is Rс = 6.95.108 m. Then the volume of the Sun is equal to V = 14.06.1026 m3. It turns out that 97.45% of the total volume of the Sun is a cold body.

As has happened more than once in history, it is necessary to restore the truth of a unique natural phenomenon, which follows the law of conservation of energy: with what temperature difference heat is transferred from interstellar space to the cold center of the star, with the same temperature difference the star radiates heat into interstellar space.

The action of the gravitational mechanism on the Sun is a continuous process that occurs due to the pressure of microparticles (on bodies, particles) during their thermodynamic transition from “warm” interstellar space with a temperature TR = 2.7 K to the cold region of the center of the Sun Txc = 0.05728 K - refrigerator, output field of the fundamental core.

Gravity on the Sun is equal to: ggr = TR / Txc = 2.7K / 0.05728K = 47.14 On Earth, the temperature of the refrigerator is Txz = 0.275K and gravity on Earth is: ggr = TR / Txc = 2.7K / 0.275K = 9.81 The release of solar plasma - solar particles T = 6000K: into the temperature field of the Earth T3 = 26.5K - goes with a coefficient g = 226; in the temperature field Tα = 21.89 K - between Mars and Jupiter g = 274. Average temperature of the Sun's corona: T = 6000 K.274 = 1.65 .106 K To discard the giant planets, the temperature of the Sun's corona: T = ~ 2 mil.deg. With what force Fthrus the Sun throws the planets away with its particles, with the same force Fthrust the planets rush towards the cold center of the Sun: Fthrust = Fthrust

The Sun, proton, neutron, atom, have centers of cold where cosmic microparticles with a temperature T = 2.47 enter along magnetic force lines. 10-12 K - Newtons, which unite the entire stellar world of the Galaxy, all atoms into a single thermodynamic space.

Study of ultraviolet radiation from the Sun. (Internet - photo)

/Photo of the ESSA-7 spacecraft (USA) 11/23/1968/Research of ultraviolet radiation from the Sun. (Internet - photo)

The Sun does not have a core with a temperature of 15 mil. degrees - this is powerful x-ray radiation (see table A). On the surface of the Sun, where T = 6000K, the dark core would definitely be highlighted. But it is not there, see Fig. 1 - 8a.

It is known that aggressive ultraviolet radiation comes from the rarefied plasma of the Sun's corona and is delayed by the Earth's atmosphere.

But what will happen if the X-ray radiation from the hot core penetrates unhindered to the surface of the planet? - everything will be burned out: the plant and living world will be completely absent on Earth. By the way, a photograph of the Earth was taken from space, where the solid core of the Earth is highlighted as a dark spot in the center.

Earth from space from the North Pole.

/Photo of the ESSA-7 spacecraft (USA) November 23, 1968/

The ratio of the diameter of the Earth to the diameter of the dark disk d in the center of the pole, according to the dimensions from the photo: Dз / d = 5.3. This value is equal to the ratio of the real diameter of the Earth Dз to the diameter of the solid core dа in the center of the planet:

Dз/дя = 12.74. 103 km / 2.4. 103 km = 5.3.

Consequently, the dark disk is the solid core of the Earth with a proton shock wave T = 6000K - the earth's sun, against a light temperature background T = 260K of the Earth's surface.

It is necessary to restore historical justice and give people true knowledge about the theory of the structure of the Sun. And don’t force everyone to dance, like the aborigines, around a burning fire - the hot core of the Sun up to 15 mil. degrees, which has never existed in nature. It is necessary to shake up, urgently remove everything that is unnecessary and give a person the opportunity to understand the full depth of the universe of the surrounding nature.

The sun is our wealth, it is happiness, smiles, joy in the first rays of the sun. And it would be fair to hold a holiday in every school, in every city - a carnival under the motto: “Hello, Sun!” . This holiday will open a new era of knowledge about the Sun and forever close the page of injustice towards the main source of heat and light, the Earth.

Used Books:

1. Aleksandrov E. In search of the fifth force. Journal “Science and Life” No. 1, 1988. 2. Badin Yu. Shock-wave thermodynamics. The mechanism of gravity. Ed. "Ecology +" St. Petersburg - Tolyatti, 2009. 3. Badin Yu. The sun is a cold body with a hot photosphere. The mechanism of gravity. Ed. "Ecology +" St. Petersburg - Togliatti, 2015. 4. Byalko A. Our planet - Earth. Ed. "The science". Moscow, 1983 5. Weinberg S. Discovery of subatomic particles, Ed. "Mir", Moscow 1986 6. Vorontsov-Velyaminov B. Astronomy. Ed. “Bustard”, Moscow, 2001. 7. Glinka N. General chemistry. Goskhimizdat. Moscow, 1956 8. Zharkov V. Internal structure of the Earth and planets. Ed. Science, Moscow, 1983. 9. Klimishin I. Discovery of the Universe. Ed. "Science", Moscow, 1987. 10. Kulikov K., Sidorenkov N. Planet Earth. Ed. "Science", Moscow, 1977. 11. Narlikar D. Gravity without formulas. Ed. "World". Moscow, 1985 12. Rodionov V. The place and role of the world ether in the true table D.I. Mendeleev. Journal of the Russian Physical Society (ZHRFM, 2001, 1-12, pp. 37-51) 13. Feynman R. The nature of physical laws. Ed. "Science", Moscow, 1987.

Corresponding member of MANEB Yu. M. Badin, own correspondent of "Seven Versts"

Address: 445028, Tolyatti, PO Box 1078.

Tel. cell 8 917 133 43 16.

There are trillions of stars in the Universe. We don't even see most of them, and those that are visible to our eyes can be bright or very dim, depending on their size and other properties. What do we know about them? Which star is the smallest? Which one is the hottest?

Stars and their varieties

Our Universe is full of interesting objects: planets, stars, nebulae, asteroids, comets. Stars are massive balls of gases. The force of their own gravity helps them maintain balance. Like all cosmic bodies, they move in space, but due to the great distance it is difficult to notice.

Thermonuclear reactions occur inside stars, causing them to emit energy and light. Their brightness varies considerably and is measured in magnitudes. In astronomy, each quantity corresponds to a certain number, and the lower it is, the lower the brightness of the star. The smallest star in size is called a dwarf; there are also normal stars, giants and supergiants.

In addition to brightness, they also have a temperature, due to which stars emit a different spectrum. The hottest are blue, followed (in descending order) by blue, white, yellow, orange and red. Stars that do not fit into any of these parameters are called peculiar.

The hottest stars

When we talk about the temperature of stars, we mean the surface characteristics of their atmospheres. The internal temperature can only be determined through calculations. How hot a star is can be judged by its color or spectral class, which is usually designated by the letters O, B, A, F, G, K, M. Each of them is divided into ten subclasses, which are designated by numbers from 0 to 9.

Class O is among the hottest. Their temperature ranges from 50 to 100 thousand degrees Celsius. However, scientists recently dubbed the Butterfly Nebula, the temperature of which reaches 200 thousand degrees, the hottest star.

Other hot stars are blue supergiants, for example, Rigel Orionis, Alpha Giraffe, Gamma. Cool stars are M-class dwarfs. WISE J085510.83-071442 is considered the coldest in the Universe. The temperature of the star reaches -48 degrees.

Dwarf stars

A dwarf is the direct opposite of a supergiant, the smallest star in size. They are small in size and luminosity, and may even be smaller than the Earth. Dwarfs make up 90% of the stars in our galaxy. They are significantly smaller than the Sun, however, they are superior to the naked eye; they are almost impossible to see in the night sky.

Red dwarfs are considered the smallest. They have a modest mass and are cool compared to other stars. Their spectral class is designated by the letters M and K. Temperatures can reach from 1,500 to 1,800 degrees Celsius.

Star 61 in the constellation Cygnus is the smallest star that can be seen without professional optics. It emits a dim light and is located 11.5 light years away. Slightly larger in size is an orange dwarf located at a distance of ten light years.

The closest to us is Proxima; a person could reach it only after 18 thousand years. It is a red dwarf that is 1.5 times larger than Jupiter. It is located only 4.2 light years from the Sun. The luminary is surrounded by other small stars, but they have not been studied due to their low brightness.

Which star is the smallest?

Not all stars are familiar to us. There are hundreds of billions of them in the Milky Way galaxy alone. Of course, scientists have studied only a small part of them. The smallest star known to date in the Universe is called OGLE-TR-122b.

It is a double star, meaning it is connected by a gravitational field to another star. Their mutual rotation around each other's masses lasts seven and a half days. The system was discovered in 2005 during the Optical Gravitational Lens Experiment, from the English abbreviation of which it was named.

The smallest star is a red dwarf in the southern hemisphere sky. Its radius is 0.12 that of the sun, and its mass is 0.09. It is 100 times more massive than Jupiter, and 50 times more dense than the Sun.

The discovery of this star system confirmed scientists' theory that a star can be slightly larger than the average planet if its mass is at least ten times less than the Sun. Most likely, there are smaller stars in the Universe, but modern technology does not allow them to be seen.

Fate of the stars

Stars, like people, are born, live and die... And each, one might say, has its own destiny. Some go through their life path without incident, gracefully fading away as a red giant, while others explode as supernovae. It is known that the surface of a star is very hot. Are there cold stars? It turns out that they do! Stars are the source of heat and light in the Universe.

Coffee cup temperature

There are blue giants, very hot and bright, and there are red giants - cooling and dying stars. Until recently, it was believed that the red giant was the coldest star. But after the invention of ultra-sensitive telescopes, discoveries began to pour in like from a cornucopia.

It turned out, for example, that there are many more types of stars than scientists thought. And their temperature may be much lower than expected. As it turned out, the temperature of the coldest star known to scientists today is +98 o C. This is the temperature of a cup of morning coffee! It turned out that there are many such objects in the Universe - they were given the name “brown dwarfs”.

In the depths of a star

In order for a cauldron of thermonuclear reactions to flare up in the depths of a star, it needs a mass and temperature sufficient for the occurrence and maintenance of a thermonuclear fusion reaction. If the star has not gained weight, then there will be no heat, or rather, there will be, but just a little. It’s surprising that astronomers still classify such “absurd” objects as stars.

In the constellation Bootes

Until recently, it was believed that the coldest star has a temperature of +287 o C. Now a new record holder has appeared. However, there is no unanimity among scientists: for example, Michael Lee from the University of Hawaii believes that from now on “brown dwarfs” can be classified as cold planets, because according to his forecasts, there may be water vapor in the atmosphere of the newly discovered star...

Astronomers from the Hawaiian Observatory discovered a new object. This “star” is located in the constellation Bootes, relatively close, by cosmic standards, from Earth - at a distance of 75 light years, and bears the proud, albeit indigestible, name CFBDSIR 1458 10ab.

Paradox: cold stars

When we talk about stars, we usually mean celestial bodies heated to incredibly high temperatures. And the temperatures there are truly gigantic. After all, even the surface of the closest star to us - the Sun, with a temperature of 6000 degrees, can be considered only slightly heated in comparison with those “torches” of the Universe, the temperature of which reaches several tens and hundreds of thousands of degrees. Such “hot” objects include white dwarfs with temperatures of 200,000 degrees.

It's hard to believe, but it turns out that there are stars that are many times colder than the Sun. These are the so-called brown dwarfs. We will return to them in Chapter 7.

At one time, the record holder in this temperature category was a star designated in catalogs as CFBDS0059. The temperature of this star, according to various sources, ranges from 180 to 350 degrees Celsius. And this is almost the same for a star as Antarctica is for the Earth.

Brown dwarf in the constellation Bootes

Astronomers call stars with such low temperatures brown dwarfs. In fact, this is a special class of celestial bodies, occupying an intermediate position between stars and planets. Moreover, in the early stages of their evolution, that is, in their youth, brown dwarfs are stars. When they “grow old,” they move to the group of planets like Jupiter, that is, giant planets.

Experts often call brown dwarfs “stars that never happened.” This is due to the fact that although thermonuclear reactions take place in them, they cannot compensate for the energy spent on radiation and therefore cool down over time. But they cannot be called planets for the reason that they do not have a clear morphological structure: they have neither a core nor a mantle and are dominated by convection currents. And since such a structure is characteristic of stars, brown dwarfs ended up in this category of celestial bodies.

In accordance with the generally accepted theory of the structure and evolution of stars, it is generally accepted that a celestial body becomes a sun if its weight reaches 80 times the mass of Jupiter. This is due to the fact that with a lower mass, thermonuclear reactions that provide it with the necessary energy will not be able to take place in the star.

For a brown dwarf to appear, a celestial object only needs to have a weight equal to 13 Jupiter masses. By cosmic standards, this is not a very large value.

Since 1995, when the existence of these cosmic bodies was confirmed by real research, more than a hundred of them have already been discovered. Scientists divided them all into two groups: hotter dwarfs belong to the L-class, and cooler ones belong to the T-class.

But the newly discovered cold star CFBDS0059 did not find a place in this classification, and it had to be allocated a separate “room” - the Y-class.

The mass of this star is from 15 to 30 times the mass of Jupiter. It is located at a distance of 40 light years from Earth. The peculiarity of this star is that, due to its low temperature, it is extremely dim, and its radiation is recorded mainly in the infrared region of the spectrum.

But very little time passed, and in 2011, astronomers discovered an even cooler brown dwarf. They saw it using a ten-meter telescope located on the island of Mauna Kea. Moreover, the signal from this celestial object was so weak that it was difficult to isolate it from the general cosmic noise.

The newly discovered brown dwarf received the classification number CFBDSIR J1458+1013B. Unlike its previously discovered “ice” brother, it is part of a pair system. His partner is also a brown dwarf, but already quite ordinary. This structure is located at a distance of 75 light years from Earth.

The temperature of the new record holder fluctuates somewhere in the region of 60-135 degrees Celsius. This means that this brown dwarf may contain water, and in a liquid state.

True, hot water vapor was also recorded in the atmosphere of brown dwarfs before. But on this incredibly cold dwarf, scientists suggest, it may even be in the form of clouds.

From the book Encyclopedic Dictionary (P) author Brockhaus F.A.

Paradox Paradox (para-dokew-seem) is an opinion that diverges from the generally accepted one. P. can express both a true opinion and a false one, depending on what is generally accepted. The desire for paradoxical statements, characteristic of many authors, often characterizes

From the book In the beginning there was a word. Aphorisms author

Paradox in music Paradox in music - everything exquisite, strange, as well as the names of singers or instrumentalists who won championships at the Olympic Games

From the book Everything is Science. Aphorisms author Dushenko Konstantin Vasilievich

Paradox and banality Paradox: a logical statement about an absurd reality. Henryk Jagodzinski (b. 1928), Polish satirist A paradox is two ends of one truth. Wladyslaw Grzegorczyk, Polish aphorist The road to truth is paved with paradoxes. Oscar Wilde (1854–1900),

From the book Great Soviet Encyclopedia (GI) by the author TSB

PARADOX Paradox: a logical statement about an absurd reality. Henryk Jagodzinski We speak of paradoxes because of the impossibility of finding truths that are not banal. Jean Condorcet Any precise definition of the world will be a paradox. Stanislav Jerzy Lec Paradox –

From the book Great Soviet Encyclopedia (GR) by the author TSB

From the book Great Soviet Encyclopedia (ZE) by the author TSB

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From the book Great Soviet Encyclopedia (PA) by the author TSB

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From the book The Complete Illustrated Encyclopedia of Our Misconceptions [with transparent pictures] author Mazurkevich Sergei Alexandrovich

From the book Great Encyclopedia of Canning author Semikova Nadezhda Aleksandrovna

Fools have cold ears. Absolutely all people, regardless of their mental abilities, have ear temperatures lower than body temperature by 1.5–2

From the book Philosophical Dictionary author Comte-Sponville Andre

Cold Feet Some parents often panic when their young children, despite being kept warm (and even too warm), constantly have cold hands and feet. And the parents themselves, and numerous “advisers” in the person of grandparents, relatives and friends

The stars we observe vary in both color and brightness. The brightness of a star depends both on its mass and on its distance. And the color of the glow depends on the temperature on its surface. The coolest stars are red. And the hottest ones have a bluish tint. White and blue stars are the hottest, their temperature is higher than the temperature of the Sun. Our star, the Sun, belongs to the class of yellow stars.

How many stars are there in the sky?
It is almost impossible to calculate even approximately the number of stars in the part of the Universe known to us. Scientists can only say that there may be about 150 billion stars in our Galaxy, which is called the Milky Way. But there are other galaxies! But people know much more accurately the number of stars that can be seen from the surface of the Earth with the naked eye. There are about 4.5 thousand such stars.

How are stars born?
If the stars light up, does that mean someone needs it? In the endless space there are always molecules of the simplest substance in the Universe - hydrogen. Somewhere there is less hydrogen, somewhere more. Under the influence of mutual attractive forces, hydrogen molecules are attracted to each other. These attraction processes can last for a very long time - millions and even billions of years. But sooner or later, the hydrogen molecules are attracted so close to each other that a gas cloud forms. With further attraction, the temperature in the center of such a cloud begins to rise. Another millions of years will pass, and the temperature in the gas cloud may rise so much that a thermonuclear fusion reaction will begin - hydrogen will begin to turn into helium and a new star will appear in the sky. Any star is a hot ball of gas.

The lifespan of stars varies significantly. Scientists have found that the greater the mass of a newborn star, the shorter its lifespan. The lifespan of a star can range from hundreds of millions of years to billions of years.

Light year
A light year is the distance covered in a year by a beam of light traveling at a speed of 300 thousand kilometers per second. And there are 31,536,000 seconds in a year! So, from the closest star to us, called Proxima Centauri, a beam of light travels for more than four years (4.22 light years)! This star is 270 thousand times farther from us than the Sun. And the rest of the stars are much further away - tens, hundreds, thousands and even millions of light years from us. This is why stars appear so small to us. And even in the most powerful telescope, unlike planets, they are always visible as dots.

What is a "constellation"?
Since ancient times, people have looked at the stars and seen in the bizarre figures that form groups of bright stars, images of animals and mythical heroes. Such figures in the sky began to be called constellations. And, although in the sky the stars included by people in this or that constellation are visually close to each other, in outer space these stars can be located at a considerable distance from each other. The most famous constellations are Ursa Major and Ursa Minor. The fact is that the constellation Ursa Minor includes the Polar Star, which is pointed to by the north pole of our planet Earth. And knowing how to find the North Star in the sky, any traveler and navigator will be able to determine where north is and navigate the area.


Supernovae
Some stars, at the end of their lives, suddenly begin to glow thousands and millions of times brighter than usual, and eject huge masses of matter into the surrounding space. It is commonly said that a supernova explosion occurs. The glow of the supernova gradually fades and eventually only a luminous cloud remains in the place of such a star. A similar supernova explosion was observed by ancient astronomers in the Near and Far East on July 4, 1054. The decay of this supernova lasted 21 months. Now in the place of this star there is the Crab Nebula, known to many astronomy lovers.

To summarize this section, we note that

V. Types of stars

Basic spectral classification of stars:

Brown dwarfs

Brown dwarfs are a type of star in which nuclear reactions could never compensate for the energy lost to radiation. For a long time, brown dwarfs were hypothetical objects. Their existence was predicted in the middle of the 20th century, based on ideas about the processes occurring during the formation of stars. However, in 2004, a brown dwarf was discovered for the first time. To date, quite a lot of stars of this type have been discovered. Their spectral class is M - T. In theory, another class is distinguished - designated Y.

White dwarfs

Soon after the helium flash, carbon and oxygen “ignite”; each of these events causes a strong restructuring of the star and its rapid movement along the Hertzsprung-Russell diagram. The size of the star's atmosphere increases even more, and it begins to intensively lose gas in the form of scattering streams of stellar wind. The fate of the central part of the star depends entirely on its initial mass: the core of the star can end its evolution as a white dwarf (low-mass stars), if its mass in the later stages of evolution exceeds the Chandrasekhar limit - as a neutron star (pulsar), if the mass exceeds The Oppenheimer-Volkov limit is like a black hole. In the last two cases, the completion of the evolution of stars is accompanied by catastrophic events - supernova explosions.
The vast majority of stars, including the Sun, end their evolution by contracting until the pressure of degenerate electrons balances gravity. In this state, when the size of the star decreases by a hundred times, and the density becomes a million times higher than the density of water, the star is called a white dwarf. It is deprived of energy sources and, gradually cooling down, becomes dark and invisible.

Red giants

Red giants and supergiants are stars with a fairly low effective temperature (3000 - 5000 K), but with enormous luminosity. The typical absolute magnitude of such objects is 3m-0m (luminosity class I and III). Their spectrum is characterized by the presence of molecular absorption bands, and the maximum emission occurs in the infrared range.

Variable stars

A variable star is a star whose brightness has changed at least once in its entire observation history. There are many reasons for variability and they can be associated not only with internal processes: if the star is double and the line of sight lies or is at a slight angle to the field of view, then one star, passing through the disk of the star, will eclipse it, and the brightness may also change if the light from the star will pass through a strong gravitational field. However, in most cases, variability is associated with unstable internal processes. The latest version of the general catalog of variable stars adopts the following division:
Eruptive variable stars- these are stars that change their brightness due to violent processes and flares in their chromospheres and coronas. The change in luminosity usually occurs due to changes in the envelope or mass loss in the form of variable-intensity stellar wind and/or interaction with the interstellar medium.
Pulsating Variable Stars are stars that exhibit periodic expansion and contraction of their surface layers. Pulsations can be radial or non-radial. Radial pulsations of a star leave its shape spherical, while non-radial pulsations cause the star's shape to deviate from spherical, and neighboring zones of the star may be in opposite phases.
Rotating Variable Stars- these are stars whose brightness distribution over the surface is non-uniform and/or they have a non-ellipsoidal shape, as a result of which, when the stars rotate, the observer records their variability. Inhomogeneities in surface brightness can be caused by spots or temperature or chemical irregularities caused by magnetic fields whose axes are not aligned with the star's rotation axis.
Cataclysmic (explosive and nova-like) variable stars. The variability of these stars is caused by explosions, which are caused by explosive processes in their surface layers (novae) or deep in their depths (supernovae).
Eclipsing binary systems.
Optical variable binary systems with hard X-ray emission
New Variable Types- types of variability discovered during the publication of the catalog and therefore not included in already published classes.

New

A nova is a type of cataclysmic variable. Their brightness does not change as sharply as that of supernovae (although the amplitude can be 9m): a few days before the maximum, the star is only 2m fainter. The number of such days determines which class of novae the star belongs to:
Very fast if this time (denoted as t2) is less than 10 days.
Fast - 11 Very slow: 151 Extremely slow, staying close to the maximum for years.

There is a dependence of the maximum brightness of the nova on t2. Sometimes this dependence is used to determine the distance to a star. The flare maximum behaves differently in different ranges: when in the visible range there is already a decline in radiation, in the ultraviolet it is still growing. If a flash is also observed in the infrared range, then the maximum will be reached only after the glare in the ultraviolet subsides. Thus, the bolometric luminosity during a flare remains unchanged for quite a long time.

In our Galaxy, two groups of novae can be distinguished: new disks (on average, they are brighter and faster), and new bulges, which are a little slower and, accordingly, a little fainter.

Supernovae

Supernovae are stars that end their evolution in a catastrophic explosive process. The term “supernovae” was used to describe stars that flared up much (by orders of magnitude) more powerfully than the so-called “novae.” In fact, neither one nor the other are physically new; existing stars always flare up. But in several historical cases, those stars flared up that were previously practically or completely invisible in the sky, which created the effect of the appearance of a new star. The type of supernova is determined by the presence of hydrogen lines in the flare spectrum. If it is there, then it is a type II supernova, if not, then it is a type I supernova.

Hypernovae

Hypernova - the collapse of an exceptionally heavy star after there are no more sources left in it to support thermonuclear reactions; in other words, it is a very large supernova. Since the early 1990s, stellar explosions have been observed so powerful that the force of the explosion exceeded the power of an ordinary supernova by about 100 times, and the energy of the explosion exceeded 1046 joules. In addition, many of these explosions were accompanied by very strong gamma-ray bursts. Intensive study of the sky has found several arguments in favor of the existence of hypernovae, but for now hypernovae are hypothetical objects. Today the term is used to describe the explosions of stars with masses ranging from 100 to 150 or more solar masses. Hypernovae could theoretically pose a serious threat to the Earth due to a strong radioactive flare, but at present there are no stars near the Earth that could pose such a danger. According to some data, 440 million years ago there was a hypernova explosion near the Earth. It is likely that the short-lived nickel isotope 56Ni fell to Earth as a result of this explosion.

Neutron stars

In stars more massive than the Sun, the pressure of degenerate electrons cannot contain the compression of the core, and it continues until most of the particles turn into neutrons, packed so tightly that the size of the star is measured in kilometers, and its density is 280 trillion. times the density of water. Such an object is called a neutron star; its equilibrium is maintained by the pressure of the degenerate neutron matter.

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