What color are the stars

Star colors. The stars have a variety of colors. Arcturus has a yellow-orange hue, Rigel is white-blue, Antares is bright red. The dominant color in the spectrum of a star depends on the temperature of its surface. The gas envelope of a star behaves almost like an ideal radiator (absolutely black body) and completely obeys the classical radiation laws of M. Planck (1858–1947), J. Stefan (1835–1893) and V. Wien (1864–1928), which relate body temperature and the nature of its radiation. Planck's law describes the distribution of energy in the spectrum of a body. He indicates that with increasing temperature, the total radiation flux increases, and the maximum in the spectrum shifts towards short waves. The wavelength (in centimeters) that accounts for the maximum radiation is determined by Wien's law: l max = 0.29/ T. It is this law that explains the red color of Antares ( T= 3500 K) and Rigel's bluish color ( T= 18000 K). Stefan's law gives the total radiant flux at all wavelengths (in watts per square meter): E = 5,67" 10 –8 T 4 .

Spectra of stars. The study of stellar spectra is the foundation of modern astrophysics. The spectrum can be used to determine the chemical composition, temperature, pressure and velocity of gas in the star's atmosphere. The Doppler shift of the lines is used to measure the speed of the star itself, for example, along the orbit in a binary system.

In the spectra of most stars, absorption lines are visible; narrow gaps in the continuous distribution of radiation. They are also called Fraunhofer or absorption lines. They are formed in the spectrum because the radiation from the hot lower layers of the star's atmosphere, passing through the colder upper layers, is absorbed at certain wavelengths characteristic of certain atoms and molecules.

The absorption spectra of stars vary greatly; however, the intensity of the lines of any chemical element does not always reflect its true amount in the stellar atmosphere: to a much greater extent, the shape of the spectrum depends on the temperature of the stellar surface. For example, iron atoms are found in the atmosphere of most stars. However, the lines of neutral iron are absent in the spectra of hot stars, since all the iron atoms there are ionized. Hydrogen is the main component of all stars. But the optical lines of hydrogen are not visible in the spectra of cold stars, where it is underexcited, and in the spectra of very hot stars, where it is fully ionized. But in the spectra of moderately hot stars with a surface temperature of approx. At 10,000 K, the most powerful absorption lines are the lines of the Balmer series of hydrogen, which are formed during the transitions of atoms from the second energy level.

The gas pressure in the star's atmosphere also has some effect on the spectrum. At the same temperature, the lines of ionized atoms are stronger in low-pressure atmospheres, because there these atoms are less likely to capture electrons and therefore live longer. Atmospheric pressure is closely related to the size and mass, and hence to the luminosity of a star of a given spectral type. Having established the pressure from the spectrum, it is possible to calculate the luminosity of the star and, comparing it with the visible brightness, determine the "distance modulus" ( M- m) and the linear distance to the star. This very useful method is called the method of spectral parallaxes.

Color index. The spectrum of a star and its temperature are closely related to the color index, i.e. with the ratio of the brightness of the star in the yellow and blue ranges of the spectrum. Planck's law, which describes the distribution of energy in the spectrum, gives an expression for the color index: C.I. = 7200/ T- 0.64. Cold stars have a higher color index than hot ones, i.e. cool stars are relatively brighter in yellow than in blue. Hot (blue) stars appear brighter on conventional photographic plates, while cool stars appear brighter to the eye and special photographic emulsions that are sensitive to yellow rays.

Spectral classification. All the variety of stellar spectra can be put into a logical system. The Harvard spectral classification was first introduced in Henry Draper's catalog of stellar spectra, prepared under the guidance of E. Pickering (1846–1919). First, the spectra were sorted by line intensities and labeled with letters in alphabetical order. But the physical theory of spectra developed later made it possible to arrange them in a temperature sequence. The letter designation of the spectra has not been changed, and now the order of the main spectral classes from hot to cold stars looks like this: O B A F G K M. Additional classes R, N and S denote spectra similar to K and M, but with a different chemical composition. Between each two classes, subclasses are introduced, indicated by numbers from 0 to 9. For example, the spectrum of type A5 is in the middle between A0 and F0. Additional letters sometimes mark the features of stars: “d” is a dwarf, “D” is a white dwarf, “p” is a peculiar (unusual) spectrum.

The most accurate spectral classification is the MK system created by W. Morgan and F. Keenan at the Yerkes Observatory. This is a two-dimensional system in which the spectra are arranged both by temperature and by the luminosity of stars. Its continuity with the one-dimensional Harvard classification is that the temperature sequence is expressed by the same letters and numbers (A3, K5, G2, etc.). But additional luminosity classes are introduced, marked with Roman numerals: Ia, Ib, II, III, IV, V and VI, respectively, indicating bright supergiants, supergiants, bright giants, normal giants, subgiants, dwarfs (main sequence stars) and subdwarfs. For example, the designation G2 V refers to a star like the Sun, while the designation G2 III indicates that it is a normal giant with a temperature about the same as that of the Sun.

HARVARD SPECTRAL CLASSIFICATION

Spectral class

Effective temperature, K

Color

26000–35000

Blue

12000–25000

white-blue

8000–11000

White

6200–7900

yellow white

5000–6100

Yellow

3500–4900

Orange

2600–3400

Red

The stars that we observe vary both in color and brightness. The brightness of a star depends on both its mass and its distance. And the color of the glow depends on the temperature on its surface. The coldest stars are red. And the hottest ones are 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 in the sky?
It is practically impossible to calculate even at least approximately the number of stars in the part of the Universe known to us. Scientists can only say that in our Galaxy, which is called the "Milky Way", there may be about 150 billion stars. But there are other galaxies too! But much more precisely, people know 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 are lit, does anyone need it? In the boundless outer space there are always molecules of the simplest substance in the Universe - hydrogen. Somewhere there is less hydrogen, somewhere more. Under the action of forces of mutual attraction, hydrogen molecules are attracted to each other. These processes of attraction can last for a very long time - millions and even billions of years. But sooner or later, hydrogen molecules are attracted so close to each other that a gas cloud is formed. With further attraction, the temperature in the center of such a cloud begins to rise. Millions of years more will pass, and the temperature in the gas cloud can 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 greatly. Scientists have found that the greater the mass of a newborn star, the shorter its lifespan. The lifetime of a star can range from hundreds of millions of years to billions of years.

Light year
A light year is the distance that a ray of light travels in a year at a speed of 300,000 kilometers per second. And there are 31536000 seconds in a year! So, from the star closest to us called Proxima Centauri, a beam of light flies 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 the planets, they are always visible as points.

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 a particular constellation are visually next to each other, in outer space these stars can be at a considerable distance from each other. The most famous constellations are Ursa Major and Ursa Minor. The fact is that the North Star, which is indicated by the north pole of our planet Earth, enters the constellation Ursa Minor. And knowing how to find the North Star in the sky, any traveler and navigator will be able to determine where the north is and navigate the terrain.


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

Summing up this section, we note that

v. Types of stars

The main 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 first discovered. To date, a lot of stars of this type have been discovered. Their spectral class is M - T. In theory, one more class is distinguished - denoted by Y.

white dwarfs

Shortly after a helium flash, carbon and oxygen "light up"; each of these events causes a strong rearrangement 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 expanding stellar wind streams. The fate of the central part of a star depends entirely on its initial mass: the core of a 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 factor of a hundred and the density becomes a million times higher than that of water, the star is called a white dwarf. It is deprived of sources of energy and, gradually cooling down, becomes dark and invisible.

red giants

Red giants and supergiants are stars with a rather low effective temperature (3000 - 5000 K), but with a huge luminosity. Typical absolute stellar magnitude of such objects? 3m-0m (I and III class of luminosity). Their spectrum is characterized by the presence of molecular absorption bands, and the emission maximum falls on the infrared range.

variable stars

A variable star is a star whose brightness has changed at least once in the entire history of its observation. There are many reasons for the 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 small angle to the field of view, then one star, passing through the disk of the star, will outshine it, and the brightness can 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. In the latest version of the general catalog of variable stars, the following division is adopted:
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 is usually due to changes in the envelope or loss of mass in the form of a stellar wind of varying intensity and/or interaction with the interstellar medium.
Pulsating Variable Stars are stars showing 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 adjacent zones of the star can be in opposite phases.
Rotating variable stars- these are stars, in which the distribution of brightness 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 fixes their variability. Surface brightness inhomogeneities can be caused by the presence of spots or thermal or chemical irregularities caused by magnetic fields whose axes do not coincide with the axis of rotation of the star.
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-rays
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 a star belongs to:
Very fast if this time (referred to as t2) is less than 10 days.
Quick - 11 Very slow: 151 Extremely slow, being near the maximum for years.

There is a dependence of the maximum brightness of the nova on t2. Sometimes this relationship is used to determine the distance to a star. The flare maximum behaves differently in different ranges: when a decrease in radiation is already observed in the visible range, an increase still continues in the ultraviolet. If a flash is also observed in the infrared range, then the maximum will be reached only after the brightness in the ultraviolet begins to decline. 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 slightly slower and, accordingly, slightly weaker.

supernovae

Supernovae are stars that end their evolution in a catastrophic explosive process. The term "supernovae" was used to refer to stars that flared up much (by orders of magnitude) stronger than the so-called "new stars". In fact, neither one nor the other is physically new, already existing stars always flare up. But in several historical cases, those stars that were previously almost or completely invisible in the sky flared up, 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, then a type II supernova, if not, then a type I

Hypernovae

Hypernova - the collapse of an exceptionally heavy star after it no longer has sources to support thermonuclear reactions; in other words, it is a very large supernova. Since the early 1990s, such powerful explosions of stars have been observed that the force of the explosion exceeded the power of an ordinary supernova explosion 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 survey of the sky has found several arguments in favor of the existence of hypernovae, but so far, hypernovae are hypothetical objects. Today, the term is used to describe the explosions of stars with masses 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 reports, 440 million years ago there was an explosion of a hypernova near the Earth. Probably, the short-lived isotope of nickel 56Ni hit the Earth as a result of this explosion.

neutron stars

In stars more massive than the Sun, the pressure of degenerate electrons cannot hold back the collapse 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 the 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.

what color are the stars? and why?

  1. Stars come in all colors of the rainbow. Because they have different temperatures and composition.



  2. http://www.pockocmoc.ru/color.php


  3. The stars have a variety of colors. Arcturus has a yellow-orange hue, Rigel is white-blue, Antares is bright red. The dominant color in the spectrum of a star depends on the temperature of its surface. The gaseous shell of a star behaves almost like an ideal radiator (absolutely black body) and completely obeys the classical radiation laws of M. Planck (18581947), J. Stefan (18351893) and V. Wien (18641928), which relate the temperature of the body and the nature of its radiation. Planck's law describes the distribution of energy in the spectrum of a body. He indicates that with increasing temperature, the total radiation flux increases, and the maximum in the spectrum shifts towards short waves. The wavelength (in centimeters), which accounts for the maximum radiation, is determined by Wien's law: lmax = 0.29/T. It is this law that explains the red color of Antares (T = 3500 K) and the bluish color of Rigel (T = 18000 K).

    HARVARD SPECTRAL CLASSIFICATION

    Spectral class Effective temperature, KColor
    O———————————————2600035000 ——————Blue
    B ———————————————1200025000 ———-White-blue
    A ————————————————800011000 ———————White
    F ————————————————-62007900 ———-Yellow white
    G ————————————————50006100 ——————-Yellow
    K ————————————————-35004900 ————-Orange
    M ————————————————26003400 ——————Red

  4. Our sun is a pale yellow star. In general, stars have a wide variety of colors and their shades. The differences in the color of the stars are due to the fact that they have different temperatures. And here's why it's happening. Light, as you know, is a wave radiation, the wavelength of which is very small. If, however, even slightly change the length of this light, then the color of the picture that we observe will change dramatically. For example, the wavelength of red is one and a half times the wavelength of blue.

    Cluster of multicolored stars

    Scientists have formulated physical laws that relate color and temperature. The hotter the body, the greater the radiation energy from its surface and the shorter the length of the emitted waves. Therefore, if a body radiates in the blue wavelength range, then it is hotter than a body that radiates red.
    Atoms of hot gases of stars emit photons. The hotter the gas, the higher the photon energy and the shorter their wave. Therefore, the hottest new stars emit in the blue-white range. As their nuclear fuel is used up, the stars cool down. Therefore, old, cooling stars radiate in the red range of the spectrum. Middle-aged stars, such as the Sun, radiate in the yellow range.
    Our Sun is relatively close to us, and therefore we clearly see its color. Other stars are so far away from us that even with the help of powerful telescopes we cannot say with certainty what color they are. To clarify this issue, scientists use a spectrograph - a device for detecting the spectral composition of starlight.

  5. Depends on the temperature The hottest white and blue colors are the coldest red ones, but even then they have a temperature higher than any molten metal
  6. is the sun white?
  7. The perception of color is purely subjective, it depends on the reaction of the retina of the observer's eye.
  8. in the sky? I know that there are blue ones, and yellow ones, and white ones. our sun is a yellow dwarf
  9. Stars come in different colors. Blue ones have a higher temperature than red ones and more radiation energy from its surface. They also come in white, yellow, and orange, and almost all of them are made of hydrogen.
  10. Stars come in a variety of colors, almost all colors of the rainbow (for example: our Sun is yellow, Rigel is white-blue, Antares is red, etc.)

    The differences in the color of the stars are due to the fact that they have different temperatures. And here's why it's happening. Light, as you know, is a wave radiation, the wavelength of which is very small. If, however, even slightly change the length of this light, then the color of the picture that we observe will change dramatically. For example, the wavelength of red is one and a half times the wavelength of blue.

    As you know, as the temperature rises, the heated metal first begins to glow red, then yellow, and finally white. The stars shine the same way. Reds are the coldest, while whites (or even blues!) are the hottest. A newly bursting star will have a color corresponding to the energy released in its core, and the intensity of this release, in turn, depends on the mass of the star. Consequently, all normal stars are the colder the redder they are, so to speak. "Heavy" stars are hot and white, while "light", non-massive ones are red and relatively cold. We have already named the temperatures of the hottest and coldest stars (see above). Now we know that the highest temperatures correspond to blue stars, the lowest to red ones. Let us clarify that in this paragraph we were talking about the temperatures of the visible surfaces of stars, because in the center of stars (in their cores) the temperature is much higher, but it is also the highest in massive blue stars.

    The spectrum of a star and its temperature are closely related to the color index, i.e., to the ratio of the brightness of the star in the yellow and blue ranges of the spectrum. Planck's law, which describes the distribution of energy in the spectrum, gives an expression for the color index: C.I. = 7200/T 0.64. Cold stars have a higher color index than hot ones, i.e., cold stars are relatively brighter in yellow rays than in blue ones. Hot (blue) stars appear brighter on conventional photographic plates, while cool stars appear brighter to the eye and special photographic emulsions that are sensitive to yellow rays.
    Scientists have formulated physical laws that relate color and temperature. The hotter the body, the greater the radiation energy from its surface and the shorter the length of the emitted waves. Therefore, if a body radiates in the blue wavelength range, then it is hotter than a body that radiates red.
    Atoms of hot gases of stars emit photons. The hotter the gas, the higher the photon energy and the shorter their wave. Therefore, the hottest new stars emit in the blue-white range. As their nuclear fuel is used up, the stars cool down. Therefore, old, cooling stars radiate in the red range of the spectrum. Middle-aged stars, such as the Sun, radiate in the yellow range.
    Our Sun is relatively close to us, and therefore we clearly see its color. Other stars are so far away from us that even with the help of powerful telescopes we cannot say with certainty what color they are. To clarify this issue, scientists use a spectrograph - a device for detecting the spectral composition of starlight.
    HARVARD SPECTRAL CLASSIFICATION gives a temperature dependence of the color of a star, for example: 35004900 - orange, 800011000 white, 2600035000 blue, etc. http://www.pockocmoc.ru/color.php

    And another important fact: the dependence of the color of the star's glow on the mass.
    More massive normal stars have higher surface and interior temperatures. They quickly burn their nuclear fuel - hydrogen, which, in general, consists of almost all stars. Which of the two normal stars is more massive can be judged by its color: blue ones are heavier than white ones, white ones are yellow, yellow ones are orange, orange ones are red.

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 hue, 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 - 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 stars is so huge that we can see them at those far distances at which they are removed from us: tens, hundreds, thousands of light years!
Conclusions:
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 stars is so huge that we can see them at those far 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.