In ancient times, people thought that the stars were the souls of people, the living ones or the nails that held up the sky. They came up with many explanations for why the stars glow at night, and the Sun was long considered a completely different object from the stars.
The problem of thermal reactions occurring in stars in general and on the Sun, the closest star to us, in particular, has long been of concern to scientists in many areas of science. Physicists, chemists, astronomers tried to figure out what leads to the release of thermal energy, accompanied by powerful radiation.
Chemists believed that exothermic chemical reactions occur in stars, resulting in the release of a large number of heat. Physicists did not agree that reactions between substances take place in these cosmic objects, since no reactions could produce so much light over billions of years.
When Mendeleev's famous table began new era in learning chemical reactions- radioactive elements were found and soon it was the reactions of radioactive decay main reason star radiation.
The controversy stopped for a while, as almost all scientists recognized this theory as the most suitable.
Modern theory about the radiation of stars
In 1903, the already established idea of why stars shine and radiate heat was turned over by the Swedish scientist Svante Arrhenius, who electrolytic dissociation. According to his theory, the source of energy in stars is hydrogen atoms, which combine with each other and form heavier helium nuclei. These processes are caused by strong gas pressure, high density and temperature (about fifteen million degrees Celsius) and occur in the inner regions of the star. This hypothesis began to be studied by other scientists, who came to the conclusion that such a fusion reaction is enough to release the colossal amount of energy that stars produce. It is also likely that the fusion of hydrogen would allow stars to shine for several billion years.
In some stars, helium fusion has ended, but they continue to shine as long as there is enough energy.
The energy released in the interior of stars is transferred to the outer regions of the gas, to the surface of the star, from where it begins to radiate in the form of light. Scientists believe that rays of light travel from the cores of stars to the surface for long tens or even hundreds of thousands of years. After that, the radiation gets to the Earth, which also requires a lot of time. Thus, the radiation of the Sun reaches our planet in eight minutes, the light of the second nearest star, Proxima Centrauri, reaches us in more than four years, and the light of many stars that can be seen with the naked eye has traveled several thousand or even millions of years.
We never think that maybe there is some other life besides our planet, besides our solar system. Perhaps there is life on some of the planets revolving around a blue or white or red, or maybe a yellow star. Perhaps there is another such planet earth, on which the same people live, but we still do not know anything about it. Our satellites and telescopes have discovered a number of planets on which there may be life, but these planets are tens of thousands and even millions of light years away.
Blue stragglers are blue-colored stars
Stars in star clusters ball type, whose temperature is higher than the temperature of ordinary stars, and the spectrum is characterized by a significant shift to the blue region than that of cluster stars with similar luminosity, are called blue stragglers. This feature allows them to stand out relative to other stars in this cluster on the Hertzsprung-Russell diagram. The existence of such stars refutes all theories of stellar evolution, the essence of which is that for stars that arose in the same period of time, it is assumed that they will be located in a well-defined region of the Hertzsprung-Russell diagram. In this case, the only factor that affects the exact location of a star is its initial mass. The frequent occurrence of blue stragglers outside of the above curve may be a confirmation of the existence of such a thing as anomalous stellar evolution. 
Experts trying to explain the nature of their occurrence put forward several theories. The most probable of them indicates that these blue stars were binary in the past, after which the process of merging began to occur or is currently taking place. The result of the merger of two stars is the emergence of a new star, which has a much greater mass, brightness and temperature than stars of the same age.
If the correctness of this theory can somehow be proved, the theory of stellar evolution would be free of problems in the form of blue stragglers. The resulting star would have large quantity hydrogen, which would behave similarly to a young star. There are facts to support this theory. Observations have shown that stray stars are most often found in central regions globular clusters. As a result of the prevailing number of stars of unit volume there, close passages or collisions become more likely.
To test this hypothesis, it is necessary to study the pulsation of blue stragglers, since between the asteroseismological properties of merged stars and normally pulsating variables, there may be some differences. It should be noted that it is rather difficult to measure pulsations. This process is also negatively affected by the overcrowding of the starry sky, small fluctuations in the pulsations of blue stragglers, as well as the rarity of their variables.
One example of a merger could be observed in August 2008, when such an incident affected the object V1309, the brightness of which increased several tens of thousands of times after detection, and returned to its original value after several months. As a result of 6-year observations, scientists came to the conclusion that this object is two stars, the period of revolution of which around each other is 1.4 days. These facts led scientists to the idea that in August 2008 the process of merging of these two stars took place.
Blue stragglers are characterized by high torque. For example, the rotation speed of the star, which is located in the middle of the 47 Tucanae cluster, is 75 times the rotation speed of the Sun. According to the hypothesis, their mass is 2-3 times the mass of other stars that are located in the cluster. Also, with the help of research, it was found that if blue stars are close to any other stars, then the latter will have a percentage of oxygen and carbon lower than their neighbors. Presumably, the stars pull these substances from other stars moving in their orbit, as a result of which their brightness and temperature increase. The “robbed” stars reveal places where the process of transformation of the initial carbon into other elements took place.
Blue Star Names - Examples
Rigel, Gamma Sails, Alpha Giraffe, Zeta Orion, Tau Big Dog, Zeta Korma
White stars - white stars
Friedrich Bessel, who led the Koenigsberg Observatory, made an interesting discovery in 1844. The scientist noticed the slightest deviation of the brightest star in the sky - Sirius, from its trajectory in the sky. The astronomer suggested that Sirius had a satellite, and also calculated the approximate period of rotation of stars around their center of mass, which was about fifty years. Bessel did not find proper support from other scientists, because. no one could detect the satellite, although in terms of its mass it should have been comparable to Sirius.
And only 18 years later, Alvan Graham Clark, who was involved in testing best telescope At that time, a dim white star was discovered near Sirius, which turned out to be its satellite, called Sirius V.
The surface of this star white color heated to 25 thousand Kelvin, and its radius is small. With this in mind, scientists have concluded that high density satellite (at the level of 106 g / cm 3, while the density of Sirius itself is approximately 0.25 g / cm 3, and the Sun - 1.4 g / cm 3). After 55 years (in 1917), another white dwarf was discovered, named after the scientist who discovered it - van Maanen's star, which is located in the constellation Pisces.
Names of white stars - examples
Vega in the constellation Lyra, Altair in the constellation Eagle, (visible in summer and autumn), Sirius, Castor.
yellow stars - yellow stars
Yellow dwarfs are called small main sequence stars, the mass of which is within the mass of the Sun (0.8-1.4). Judging by the name, such stars have a glow yellow color, which is released during the implementation of the thermonuclear fusion process from hydrogen to helium.
The surface of such stars is heated to a temperature of 5-6 thousand Kelvin, and their spectral types are between G0V and G9V. A yellow dwarf lives for about 10 billion years. The combustion of hydrogen in a star causes it to multiply in size and become a red giant. One example of a red giant is Aldebaran. Such stars can form planetary nebulae by shedding their outer layers of gas. In this case, the core is transformed into a white dwarf, which has a high density.
If we take into account the Hertzsprung-Russell diagram, then on it the yellow stars are in the central part of the main sequence. Since the Sun can be called a typical yellow dwarf, its model is quite suitable for considering the general model of yellow dwarfs. But there are other characteristic yellow stars in the sky, whose names are Alkhita, Dabikh, Toliman, Hara, etc. These stars are not very bright. For example, the same Toliman, which, if you do not take into account Proxima Centauri, is closest to the Sun, has a magnitude of 0, but at the same time, its brightness is the highest among all yellow dwarfs. This star is located in the constellation Centaurus, it is also a link complex system, which includes 6 stars. The spectral class of Toliman is G. But Dabih, located 350 light years from us, belongs to the spectral class F. But its high brightness is due to the presence of a nearby star belonging to the spectral class - A0.
In addition to Toliman, HD82943 has spectral type G, which is located on the main sequence. This star, due to its chemical composition and temperature similar to the Sun, also has two planets. large sizes. However, the shape of the orbits of these planets is far from circular, so their approaches to HD82943 occur relatively often. Astronomers have now been able to prove that this star used to have much more planets, but over time, she swallowed them all.
Yellow Star Names - Examples
Toliman, star HD 82943, Hara, Dabih, Alhita
Red stars - red stars
If at least once in your life you have seen red stars in the sky in the lens of your telescope, which burned against a black background, then the memory this moment will help to more clearly present what will be written in this article. If you have never seen such stars, next time be sure to try to find them. 
If you undertake to compile a list of the brightest red stars in the sky, which can be easily found even with an amateur telescope, you can find that they are all carbon. The first red stars were discovered in 1868. The temperature of such red giants is low, in addition, their outer layers are filled with a huge amount of carbon. If earlier similar stars made up two spectral classes - R and N, now scientists have identified them in one general class - C. Each spectral class has subclasses - from 9 to 0. At the same time, class C0 means that the star has a high temperature, but less red than C9 stars. It is also important that all carbon-dominated stars are inherently variable: long-period, semi-regular, or irregular.
In addition, two stars, called red semi-regular variables, were included in such a list, the most famous of which is m Cephei. William Herschel also became interested in her unusual red color, who dubbed her “pomegranate”. Such stars are characterized by an irregular change in luminosity, which can last from a couple of tens to several hundred days. Such variable stars belong to the class M (cold stars, the surface temperature of which is from 2400 to 3800 K).
Given the fact that all the stars in the rating are variables, it is necessary to introduce some clarity in the designations. It is generally accepted that red stars have a name that consists of two constituent parts- letters of the Latin alphabet and the name of the constellation of the variable (for example, T Hare). The first variable that was discovered in this constellation is assigned the letter R and so on, up to the letter Z. If there are many such variables, a double combination of Latin letters is provided for them - from RR to ZZ. This method allows you to "name" 334 objects. In addition, stars can also be designated using the letter V in combination with a serial number (V228 Cygnus). The first column of the rating is reserved for the designation of variables.
The next two columns in the table indicate the location of the stars in the period 2000.0. As a result of the increased popularity of Uranometria 2000.0 among astronomy enthusiasts, the last column of the rating displays the number of the search chart for each star that is in the rating. In this case, the first digit is a display of the volume number, and the second is the serial number of the card.
The rating also displays the maximum and minimum values magnitude brilliance. It is worth remembering that a greater saturation of red color is observed in stars whose brightness is minimal. For stars whose period of variability is known, it is displayed as a number of days, but objects that do not have the correct period are displayed as Irr.
It doesn't take much skill to find a carbon star, it's enough that your telescope has enough power to see it. Even if its size is small, its pronounced red color should draw your attention. Therefore, do not be upset if you cannot immediately find them. It is enough to use the atlas to find a nearby bright star, and then already, move from it to red.
Different observers see carbon stars differently. To some, they resemble rubies or an ember burning in the distance. Others see crimson or blood red hues in such stars. For starters, there is a list of the six brightest red stars in the ranking, and if you find them, you can enjoy their beauty to the fullest.
Red Star Names - Examples
Differences in stars by color
There is a huge variety of stars with indescribable color shades. As a result, even one constellation has received the name "Jewel Box", which is based on blue and sapphire stars, and in its very center is a brightly shining orange star. If we consider the Sun, then it has a pale yellow color.
A direct factor influencing the difference in color of stars is their surface temperature. It is explained simply. Light by its nature is radiation in the form of waves. Wavelength - this is the distance between its crests, is very small. To imagine it, you need to divide 1 cm into 100 thousand identical parts. A few of these particles will make up the wavelength of light.
Considering that this number turns out to be quite small, each, even the most insignificant, change in it will cause the picture we observe to change. After all, our vision perceives different wavelengths of light waves as different colors. For example, blue has waves whose length is 1.5 times less than that of red.
Also, almost every one of us knows that temperature can have the most direct effect on the color of bodies. For example, you can take any metal object and put it on fire. As it heats up, it will turn red. If the temperature of the fire increased significantly, the color of the object would also change - from red to orange, from orange to yellow, from yellow to white, and finally from white to blue-white.
Since the Sun has a surface temperature in the region of 5.5 thousand 0 C, it is typical example yellow stars. But the hottest blue stars can warm up to 33 thousand degrees.
Color and temperature have been linked by scientists with the help of physical laws. The temperature of a body is directly proportional to its radiation and inversely proportional to the wavelength. Waves of blue color have shorter wavelengths than red. Hot gases emit photons whose energy is directly proportional to the temperature and inversely proportional to the wavelength. That is why the blue-blue range of radiation is characteristic of the hottest stars.
Since the nuclear fuel on the stars is not unlimited, it tends to be consumed, which leads to the cooling of the stars. Therefore, middle-aged stars are yellow, and we see old stars as red.
As a result of the fact that the Sun is very close to our planet, its color can be accurately described. But for stars that are a million light-years away, the task becomes more complicated. It is for this purpose that a device called a spectrograph is used. Through it, scientists pass the light emitted by the stars, as a result of which it is possible to analyze almost any star spectrally.
In addition, using the color of a star, you can determine its age, because. mathematical formulas make it possible to use spectral analysis to determine the temperature of a star, from which it is easy to calculate its age.
Video secrets of the stars watch online
Stars are the main objects of the Universe visible to us. The outer world is unusual and diverse. The theme of universal luminaries is inexhaustible. The sun was created to shine during the day, and the stars - in order to illuminate the earthly path for a person at night. This article will discuss how the light we see is formed, coming from amazing celestial bodies.
Origin
The birth of a star, as well as its extinction, can be visually seen in the night sky. Astronomers have been observing these phenomena for a long time and have already made many discoveries. All of them are described in the special scientific literature. Stars are luminous fireballs of incredibly large sizes. But why do they glow, twinkle and shimmer in different colors?
These celestial bodies are born from a diffuse gas-and-dust medium, which has arisen as a result of gravitational compression in denser layers, plus the influence of its own gravity. The composition of the interstellar medium is mainly gas (hydrogen and helium) with a dust of solid mineral particles. Our main luminary is a star named the Sun. Without it, life for everything that exists on our planet is impossible. Interestingly, many stars are much larger than the Sun. Why do we not feel their influence and can we easily exist without them?
Our source of heat and light is located close to the Earth. Therefore, for us it is essential to feel its light and warmth. The stars are hotter than the Sun, larger than it, but they are at such far distances that we can only observe their light, and then only at night.
They seem to be just shimmering dots in the night sky. Why don't we see them during the day? Starlight is like the rays from a flashlight, which you can barely see during the day, but you can’t do without it at night - it illuminates the road well.
When is the brightest and why do the stars shine in the night sky?
August is the most best month for stargazing. At this time of the year, the evenings are dark and the air is clear. It feels like you can touch the sky with your hand. Children, raising their eyes to the sky, always ask themselves the question: “Why do the stars shine and where do they fall?” The fact is that in August people often observe starfall. This is an extraordinary spectacle that beckons our eyes and souls. There is a belief that when you see a shooting star, you need to make a wish that will certainly come true.
However, what is interesting is that in fact it is not a star falling, but a meteor burning down. Whatever it was, but the phenomenon is very beautiful! Times go by, generations of people succeed each other, but the sky is still the same - beautiful and mysterious. Just like us, our ancestors looked at it, guessed the figures of various mythological characters and objects in star clusters, made wishes and dreamed.
How does light appear?
Space objects called stars emit an incredibly large amount of thermal energy. Energy emissions are accompanied by a strong emission of light, a certain part of which reaches our planet, and we have the opportunity to observe it. This is the short answer to the question: “Why do the stars shine in the sky, and are all heavenly bodies related to them?” For example, the Moon is a satellite of the Earth, and Venus is a planet solar system. We do not see their own light, but only its reflection. The stars themselves are the source of light radiation, which appears as a result of the release of energy.
Some celestial objects have white light, while others have blue or orange. There are some that spill different shades. What is the reason for this and why do the stars glow in different colors? The fact is that they are huge balls, consisting of red-hot to very high temperatures gases. As this temperature fluctuates, the stars have a different glow: the hottest are blue, followed by white, even colder - yellow, then orange and red.
flicker
Many people wonder: why do the stars glow at night and their light twinkles? First of all, they don't flicker. It just seems to us. The fact is that starlight passes through the thickness of the earth's atmosphere. A beam of light, overcoming such long distances, is subjected to a large number breaks and changes. For us, these refractions look like scintillations.
The star has its life cycle. On the different stages this cycle, it glows differently. When the time of its existence comes to an end, it begins to gradually turn into a red dwarf and cools. The radiation of a dying star pulsates. This creates the impression of flickering (blinking). During the day, the light from the star does not disappear anywhere, but it is overshadowed by too bright and close sunlight. Therefore, at night we see them due to the fact that there are no rays of the Sun.
Each star is a huge luminous ball of gas, like our Sun. A star shines because it releases a huge amount of energy. This energy is formed as a result of the so-called thermonuclear reactions.
Each star is a huge luminous ball of gas, like our Sun. A star shines because it releases a huge amount of energy. This energy is formed as a result of the so-called thermonuclear reactions.Each star contains many chemical elements. For example, the presence of at least 60 elements has been detected on the Sun. Among them are hydrogen, helium, iron, calcium, magnesium and others. 
Why do we see the Sun so small? Yes, because it is very far from us. Why do stars look so tiny? Remember how small our huge Sun seems to us - just the size of a soccer ball. This is because it is very far from us. And the stars are much, much further away! 
Stars like our Sun illuminate the Universe around them, warm, the planets surrounding them, give life. Why do they only glow at night? No, no, during the day they also shine, you just can't see them. In the daytime, our sun illuminates the blue atmosphere of the planet with its rays, which is why space is hidden behind a curtain. At night, this veil opens, and we see all the splendor of the cosmos - stars, galaxies, nebulae, comets and many other wonders of our Universe.
They are divided into spectral classes depending on their spectrum of electromagnetic radiation. From it you can get such important information about the cosmic body as temperature and pressure. upper layers, chemical composition, and other physical characteristics.
In a simple case, the spectrum can be obtained as follows: , emitted by an object, is passed through a narrow hole, behind which is a prism. The latter refracts light, which is then directed to a screen or a special film. The resulting image appears as a smooth color gradient from purple to red. A spectrum without any black lines is said to be continuous. A similar picture is observed when light is emitted by solid or liquid bodies, for example, an incandescent lamp.
Consider the following case: let there be a burner in whose flame a certain mass of salt has been placed. In the described case, a bright yellow color will be observed in the light of the flame. And if you look through these vapors, we will see a bright yellow line. This means that heated sodium vapor emits light with a yellow wavelength. This property is inherent in any substance in the gaseous state, and its spectrum is called line.
When observing the Sun, the German optician Josef Fraunhofer noted that there were some thin black lines in its continuous radiation spectrum. Later, Gustav Kirchhoff determined that any rarefied gas absorbs the rays of light of precisely those wavelengths that it emits itself, being in a state of luminescence. The black lines obtained in the continuous spectrum were called absorption lines. By applying the above laws to, scientists were able to identify the chemical composition of the star. Since the gases in the atmosphere absorbed radiation with certain wavelengths.
Subsequently, many methods appeared in spectroscopy for studying other properties of stars, that is, shifting the spectrum in a certain direction, comparison with the spectrum of a completely black body, bifurcation of superposition lines, and so on.
