The biggest stars are the color. Spectral classification of stars: color and temperature dependence

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 - blue stars

Stars located in star clusters of globular 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 a 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 contain more 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 the central regions of 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 Canis Major, Zeta Puppis

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 testing the best telescope of those times, discovered a dim white star near Sirius, which turned out to be his satellite, called Sirius B.

The surface of this white star is heated to 25 thousand Kelvin, and its radius is small. Taking this into account, scientists concluded that the satellite has a high density (at the level of 106 g/cm 3 , while the density of Sirius itself is approximately 0.25 g/cm 3 , and that of the Sun is 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 yellow glow, which is released during the thermonuclear process of fusion from helium hydrogen.

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 in a 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 large planets. However, the shape of the orbits of these planets is far from circular, so their approaches to HD82943 occur relatively often. Currently, astronomers have been able to prove that this star used to have a much larger number of planets, but over time it 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 were burning on a black background, then remembering this moment will help you more clearly imagine 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 components - the letter of the Latin alphabet and the name of the variable constellation (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 brightness values ​​of stellar magnitudes. 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 move from it to the red one.

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 a typical example of 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. Blue has 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 allow the use of 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

With a telescope, you can observe 2 billion stars up to 21 magnitudes. There is a Harvard spectral classification of stars. In it, the spectral types are arranged in order of decreasing stellar temperature. Classes are designated by letters of the Latin alphabet. There are seven of them: O - B - A - P - O - K - M.

A good indicator of the temperature of a star's outer layers is its color. Hot stars of spectral types O and B are blue; stars similar to our Sun (whose spectral type is 02) appear yellow, while stars of spectral classes K and M are red.

Brightness and color of stars

All stars have a color. There are blue, white, yellow, yellowish, orange and red stars. For example, Betelgeuse is a red star, Castor is white, Capella is yellow. By brightness, they are divided into stars of the 1st, 2nd, ... nth magnitude (n max = 25). The term "magnitude" has nothing to do with true dimensions. The magnitude characterizes the light flux coming to Earth from a star. Stellar magnitudes can be both fractional and negative. The magnitude scale is based on the perception of light by the eye. The division of stars into stellar magnitudes according to apparent brightness was carried out by the ancient Greek astronomer Hipparchus (180 - 110 BC). Hipparchus attributed the first magnitude to the brightest stars; he considered the next in brightness gradation (i.e., about 2.5 times weaker) to be stars of the second magnitude; stars weaker than stars of the second magnitude by 2.5 times were called stars of the third magnitude, etc.; stars at the limit of visibility to the naked eye were assigned a sixth magnitude.

With such a gradation of the brightness of the stars, it turned out that the stars of the sixth magnitude are weaker than the stars of the first magnitude by 2.55 times. Therefore, in 1856, the English astronomer N.K. Pogsoy (1829-1891) proposed to consider as stars of the sixth magnitude those that are exactly 100 times weaker than the stars of the first magnitude. All stars are located at different distances from the Earth. It would be easier to compare magnitudes if the distances were equal.

The magnitude that a star would have at a distance of 10 parsecs is called absolute magnitude. The absolute stellar magnitude is indicated - M, and the apparent stellar magnitude - m.

The chemical composition of the outer layers of stars, from which their radiation comes, is characterized by the complete predominance of hydrogen. In second place is helium, and the content of other elements is quite small.

Temperature and mass of stars

Knowing the spectral type or color of a star immediately gives the temperature of its surface. Since stars radiate approximately like absolutely black bodies of the corresponding temperature, the power radiated by a unit of their surface per unit time is determined from the Stefan-Boltzmann law.

The division of stars based on a comparison of the luminosity of stars with their temperature and color and absolute magnitude (Hertzsprung-Russell diagram):

1. the main sequence (in the center of it is the Sun - a yellow dwarf)
2. supergiants (large in size and high luminosity: Antares, Betelgeuse)
3. red giant sequence
4. dwarfs (white - Sirius)
5. subdwarfs
6. white-blue sequence

This division is also based on the age of the star.

The following stars are distinguished:

1. ordinary (Sun);
2. double (Mizar, Albkor) are divided into:

• a) visual double, if their duality is noticed when observing through a telescope;
• b) multiples - this is a system of stars with a number greater than 2, but less than 10;
• c) optical-double - these are stars that their proximity is the result of a random projection onto the sky, and in space they are far away;
• d) physical binaries are stars that form a single system and circulate under the action of forces of mutual attraction around a common center of mass;
• e) spectroscopic binaries are stars that, when mutually revolving, come close to each other and their duality can be determined from the spectrum;
• e) eclipsing binary - these are stars "which, when mutually revolving, block each other;

new stars- these are stars that existed for a long time, but suddenly flared up. Their brightness increased in a short time by 10,000 times (the amplitude of the change in brightness from 7 to 14 magnitudes).

supernovae- these are stars that were invisible in the sky, but suddenly flashed and increased in brightness 1000 times relative to ordinary new stars.

Pulsar- a neutron star that occurs during a supernova explosion.

Data on the total number of pulsars and their lifetimes indicate that, on average, 2-3 pulsars are born per century, which approximately coincides with the frequency of supernova explosions in the Galaxy.

Star evolution

Like all bodies in nature, stars do not remain unchanged, they are born, evolve, and finally die. Astronomers used to think that it took millions of years for a star to form from interstellar gas and dust. But in recent years, photographs have been taken of a region of the sky that is part of the Great Nebula of Orion, where a small cluster of stars has appeared over the course of several years. In the photographs of 1947, a group of three star-like objects was recorded in this place. By 1954 some of them had become oblong, and by 1959 these oblong formations had disintegrated into individual stars. For the first time in the history of mankind, people observed the birth of stars literally before our eyes.

In many parts of the sky, there are conditions necessary for the appearance of stars. When studying photographs of the hazy regions of the Milky Way, it was possible to find small black spots of irregular shape, or globules, which are massive accumulations of dust and gas. These gas and dust clouds contain dust particles that very strongly absorb the light coming from the stars behind them. The size of the globules is huge - up to several light years in diameter. Despite the fact that the matter in these clusters is very rarefied, their total volume is so large that it is quite enough to form small clusters of stars close in mass to the Sun.

In a black globule, under the influence of radiation pressure emitted by surrounding stars, the matter is compressed and compacted. Such compression proceeds for some time, depending on the sources of radiation surrounding the globule and the intensity of the latter. The gravitational forces arising from the concentration of mass in the center of the globule also tend to compress the globule, causing matter to fall towards its center. Falling, particles of matter acquire kinetic energy and heat up the gas and cloud.

The fall of matter can last hundreds of years. At first, it occurs slowly, unhurriedly, since the gravitational forces that attract particles to the center are still very weak. After some time, when the globule becomes smaller and the gravitational field increases, the fall begins to occur faster. But the globule is huge, no less than a light year in diameter. This means that the distance from its outer border to the center can exceed 10 trillion kilometers. If a particle from the edge of the globule starts to fall towards the center at a speed slightly less than 2 km/s, then it will reach the center only after 200,000 years.

The lifespan of a star depends on its mass. Stars With a mass less than that of the Sun use their nuclear fuel very sparingly and can shine for tens of billions of years. The outer layers of stars like our Sun, with masses no greater than 1.2 solar masses, gradually expand and, in the end, completely leave the core of the star. In place of the giant remains a small and hot white dwarf.

On a clear night, if you look closely, you can see a myriad of multi-colored stars in the sky. Have you ever wondered what determines the shade of their flicker, and what are the colors of the heavenly bodies?

The color of a star is determined by its surface temperature.. A scattering of luminaries, like precious stones, has infinitely different shades, like a magic palette of an artist. The hotter the object, the higher the radiation energy from its surface, which means the shorter the length of the emitted waves.

Even a slight difference in wavelength changes the color perceived by the human eye. The longest waves have a red tint, with increasing temperature it changes to orange, yellow, turns into white, and then becomes white-blue.

The gas envelope of the luminaries performs the functions of an ideal emitter. The color of a star can be used to calculate its age and surface temperature. Of course, the shade is determined not “by eye”, but with the help of a special tool - a spectrograph.

The study of the spectrum of stars is the foundation of astrophysics of our time. The colors of the heavenly bodies are most often the only information available to us about them.

blue stars

Blue stars are the most big and hot. The temperature of their outer layers is, on average, 10,000 Kelvin, and can reach 40,000 for individual stellar giants.

In this range, new stars radiate, just starting their "life journey". For example, Rigel, one of the two main luminaries of the constellation Orion, bluish-white.

yellow stars

Center of our planetary system - The sun- has a surface temperature exceeding 6000 Kelvin. From space, it and similar luminaries look dazzling white, although from Earth they seem rather yellow. Gold stars are of middle age.

Of the other luminaries known to us, a white star is also Sirius, although it is quite difficult to determine its color by eye. This is because it occupies a low position above the horizon, and on the way to us, its radiation is strongly distorted due to multiple refraction. In mid-latitudes, Sirius, often flickering, is able to demonstrate the entire color spectrum in just half a second!

red stars

Dark reddish hue have low temperature stars, for example, red dwarfs, whose mass is less than 7.5% of the weight of the Sun. Their temperature is below 3500 Kelvin, and although their glow is a rich overflow of many colors and shades, we see it as red.

Giant luminaries whose hydrogen fuel has run out also look red or even brown. In general, the emission of old and cooling stars is in this range of the spectrum.

A distinct red tint has the second of the main stars of the constellation Orion, Betelgeuse, and slightly to the right and above it is located on the sky map Aldebaran, which is orange in color.

The oldest red star in existence - HE 1523-0901 from the constellation Libra - a giant luminary of the second generation, found on the outskirts of our galaxy at a distance of 7500 light years from the Sun. Its possible age is about 13.2 billion years, which is not much less than the estimated age of the universe.

Karpov Dmitry

This is a research work of a student of the 1st grade of the MOU secondary school No. 25.

Purpose of the study: find out why the stars in the sky come in different colors.
Methods and techniques: observations, experiment, comparison and analysis of the results of observations, excursion to the planetarium, work with various sources of information.

Data received: Stars are hot balls of gas. The closest star to us is the Sun. All stars are different colors. The color of a star depends on the temperature on its surface. Thanks to the experiment, I was able to find out that the heated metal first begins to glow with red light, then yellow, and finally white with increasing temperature. Also with the stars. Reds are the coldest and whites (or even blues!) are the hottest. Heavy stars are hot and white, light, non-massive are red and relatively cold. The age of a star can also be determined by its color. Young stars are the hottest. They shine with white and blue light. Old, cooling stars emit red light. And middle-aged stars glow yellow. The energy emitted by the stars is so huge that we can see them at those distant distances at which they are removed from us: tens, hundreds, thousands of light years!
Findings:
1. The stars are colorful. The color of a star depends on the temperature on its surface.

2. By the color of a star, we can determine its age, mass.

3. We can see the stars thanks to the huge energy emitted by them.

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XIV city scientific and practical conference of schoolchildren

"First Steps in Science"

Why are the stars different colors?

G. Sochi.

Head: Mukhina Marina Viktorovna, primary school teacher

MOU secondary school №25

Sochi

2014

INTRODUCTION

You can admire the stars forever, they are mysterious and attractive. Since ancient times, people have attached great importance to these celestial bodies. Astronomers from antiquity to the present day declare that the location of the stars in the sky in a special way affects almost all aspects of human life. The stars determine the weather, make horoscopes and predictions, and lost ships find their way on the high seas. What are they really, these shining luminous dots?

The mystery of the starry sky is interesting to all children without exception. Scientists and astronomers have done a lot of research and uncovered many secrets. Many books have been written about the stars, many educational films have been shot, and yet, many children do not know all the secrets of the starry sky.

For me, the starry sky remains a mystery. The more I looked at the stars, the more questions I had. One of which was: what color are these twinkling, bewitching stars.

Purpose of the study:explain why the stars in the sky are different colors.

Tasks, which I set myself: 1. look for the answer to the question, talking with adults, reading encyclopedias, books, INTERNET materials;

2. make observations of the stars with the naked eye and with the help of a telescope;

3. prove by experiment that the color of a star depends on its temperature;

4. tell your classmates about the diversity of the starry world.

Object of study- celestial bodies (stars).

Subject of studyare the parameters of the stars.

Research methods:

• Reading special literature and watching popular science programs;
• Exploration of the starry sky using a telescope and special software;
• An experiment to study the dependence of the color of an object on its temperature.

result my work is the emergence of interest in this topic among my classmates.

Chapter 1

I often looked at the starry sky, consisting of many luminous points. The stars are especially visible at night and in cloudless weather. They have always attracted my attention with their special, bewitching radiance. Astrologers believe that they can influence the fate and future of a person. But few can answer the question of what they are.

Having studied the reference literature, I managed to find out that a star is a celestial body in which thermonuclear reactions take place, which is a massive luminous gas ball.

Stars are the most common objects in the universe. The number of existing stars is very difficult to imagine. It turns out that there are more than 200 billion stars in our galaxy alone, and there are a huge number of galaxies in the universe. With the naked eye, about 6,000 stars are visible in the sky, 3,000 in each hemisphere. The stars are at great distances from the Earth.

The most famous star that is closest to us is, of course, the Sun. That is why it seems to us that it is very large compared to the rest of the luminaries. During the day, it outshines all other stars with its light, so we cannot see them. If the Sun is at a distance of 150 million kilometers from the Earth, then another star, which is closer than the rest, the Centaur, is already located at 42,000 billion kilometers from us.

How did the sun appear? After studying the literature, I realized that, like other stars, the Sun appeared from the accumulation of cosmic gas and dust. Such a cluster is called a nebula. Gas and dust compressed into a dense mass, which heated up to a temperature of 15,000,000 kelvins. This is the temperature at the center of the sun.

Thus, I managed to find out that stars are gas balls in the Universe. But why then do they glow in different colors?

Chapter 2

First I decided to find the brightest stars. I assumed that the brightest star is the Sun. Due to the lack of special instruments, I determined the luminosity of the stars with the naked eye, then with the help of my telescope. In a telescope, the stars are visible as points of varying degrees of brightness without any details. The sun can be observed only with special filters. But not all stars can be seen, even through a telescope, and then I turned to information sources.

I made the following conclusions: the brightest stars are: 1. The giant star R136a12 (star formation region 30 Doradus) ; 2. Giant star VY SMA (in the constellation Canis Major)3. Deneb (in the constellationα Cygnus); 4. Rigel(in the constellation β Orion); 5. Betelgeuse (in the constellation α Orion). The names of the stars were helped by my dad using the Star Rover app for iPhone. At the same time, the first three of the stars have a bluish glow, the fourth is white-blue, and the fifth is reddish-orange. Scientists discovered the brightest star with the help ofNASA's Hubble Space Telescope.

During my research, I noticed that the brightness of stars depends on their color. But why are all stars different?

Let's consider the Sun, a star visible to the naked eye. From early childhood, we depict it in yellow, because this star is actually yellow. I began to study the properties of this star.The temperature on its surface is about 6000 degrees.In encyclopedias and on the INTERNET, I learned about other stars. It turned out that all the stars are of different colors. Some of them are white, others are blue, others are orange. There are white and red stars. It turns out that the color of a star depends on the temperature on its surface. The hottest stars appear white and blue to us. The temperature on their surface is from 10 to 100,000 degrees. A medium temperature star is yellow or orange in color. The coldest stars are red. The temperature on their surface is about 3,000 degrees. And these stars are many times hotter than the flames of a fire.

My parents and I conducted the following experiment: we heated an iron needle on a gas burner. At first, the needle was gray. After heating, it glowed and turned red. Her temperature increased. After cooling, the needle turned gray again. I concluded that as the temperature increases, the color of the star changes.And the stars are not the same as people. People usually blush when they are hot and blue when they are cold. But for stars, the opposite is true: the hotter the star, the bluer it is, and the colder, the

As you know, the heated metal first begins to glow red, then yellow and, finally, white with increasing temperature. Also with the stars. Reds are the coldest and whites (or even blues!) are the hottest.

Chapter 3 The mass of a star and its color. Star age.

When I was 6 years old, my mother and I went to the planetarium in the city of Omsk. There I learned that all stars come in different sizes. Some are big, some are small, some are heavier, some are lighter. With the help of adults, I tried to line up the studied stars from the lightest to the heaviest. And that's what I noticed! It turned out that blue is heavier than white, white - yellow, yellow - orange, orange - red.

The age of a star can also be determined by its color. Young stars are the hottest. They shine with white and blue light. Old, cooling stars emit red light. And middle-aged stars glow yellow.

The energy emitted by the stars is so huge that we can see them at those distant distances at which they are removed from us: tens, hundreds, thousands of light years!

For us to be able to see a star, its light must pass through the air layers of the Earth's atmosphere. The oscillating layers of air somewhat refract the direct stream of light, and it seems to us that the stars twinkle. In fact, direct continuous light comes from the stars.

The Sun is not the largest star, it belongs to the stars called Yellow Dwarfs. When this star lit up, it consisted of hydrogen. But under the influence of thermonuclear reactions, this substance began to turn into helium. During the existence of this luminary (about 5 billion years), about half of the hydrogen burned out. Thus, the Sun is left to "live" as long as it already exists. When the hydrogen is almost all burnt out, this star will become larger in size and turn into a Red Giant. This will greatly affect the Earth. Unbearable heat will come on our planet, the oceans will boil away, life will become impossible.

CONCLUSION

Thus, as a result of my research, my classmates and I gained new knowledge about what stars are, as well as what determines the temperature and color of stars.

BIBLIOGRAPHICAL LIST.

Stars of different colors

Our Sun is a pale yellow star. In general, the color of the stars is a stunningly diverse palette of colors. One of the constellations is called the "Jewel Box". Sapphire blue stars are scattered across the black velvet of the night sky. Between them, in the middle of the constellation, is a bright orange star.

Differences in the color of the stars

The differences in the color of the stars are explained by the fact that the stars have different temperatures. That's why it happens. Light is wave radiation. The distance between the crests of one wave is called its length. Waves of light are very short. How much? Try dividing an inch into 250,000 equal parts (1 inch equals 2.54 centimeters). Several of these parts make up the length of a light wave.

Despite such an insignificant wavelength of light, the slightest difference between the sizes of light waves dramatically changes the color of the picture that we observe. This is due to the fact that light waves of different lengths are perceived by us as different colors. For example, the wavelength of red is one and a half times longer than the wavelength of blue. White color is a beam consisting of photons of light waves of different lengths, that is, from rays of different colors.

We know from everyday experience that the color of bodies depends on their temperature. Put the iron poker on the fire. When heated, it first turns red. Then she blushes even more. If the poker could be heated even more without melting it, then it would turn from red to orange, then yellow, then white, and finally blue-white.