The color of the stars are white blue yellow red examples. How are stars distinguished by size and color? Red Star Names - Examples

Experts put forward several theories of their occurrence. The most probable of the bottom says that such blue stars were binary for a very long time, and they had a merger process. When 2 stars unite, a new star appears with much greater brightness, mass, temperature.

Blue stars examples:

• Gamma Sails;
• Rigel;
• Zeta Orion;
• Alpha Giraffe;
• Zeta Korma;
• Tau Canis Major.

White stars - white stars

One scientist discovered a very dim white star that was a satellite of Sirius and it was named Sirius B. The surface of this unique star is heated to 25,000 Kelvin, and its radius is small.

White stars examples:

• Altair in the constellation Eagle;
• Vega in the constellation Lyra;
• Castor;
• Sirius.

yellow stars - yellow stars

Such stars have a yellow glow, and their mass is within the mass of the Sun - it is about 0.8-1.4. The surface of such stars is usually heated to a temperature of 4-6 thousand Kelvin. Such a star lives for about 10 billion years.

Yellow stars examples:

• Star HD 82943;
• Toliman;
• Dabih;
• Hara;
• Alhita.

red stars red stars

The first red stars were discovered in 1868. Their temperature is quite low, and the outer layers of red giants are filled with a lot of carbon. Previously, such stars made up two spectral classes - N and R, but now scientists have been able to identify another common class - C.

main sequence. Our star also belongs to this type -. From the point of view of stellar evolution, the main sequence is the place on the Hertzsprung-Russell diagram where the star spends most of its life.

Hertzsprung-Russell diagram.

The main sequence stars are divided into classes, which we will consider below:

Class O are blue stars, their temperature is 22,000 °C. Typical stars are Zeta in the constellation Puppis, 15 Unicorn.

Class B are white-blue stars. Their temperature is 14,000 °C. Their temperature is 14,000 °C. Typical stars: Epsilon in the constellation Orion, Rigel, Kolos.

Class A are white stars. Their temperature is 10,000 °C. Typical stars are Sirius, Vega, Altair.

Class F are white-yellow stars. Their surface temperature is 6700 °C. Typical stars Canopus, Procyon, Alpha in the constellation Perseus.

Class G are yellow stars. Temperature 5 500 °С. Typical stars: Sun (spectrum C-2), Capella, Alpha Centauri.

Class K are yellow-orange stars. Temperature 3 800 °C. Typical stars: Arthur, Pollux, Alpha Ursa Major.

Class M -. These are red stars. Temperature 1 800 °C. Typical stars: Betelgeuse, Antares

In addition to main sequence stars, astronomers distinguish the following types of stars:

A brown dwarf through the eyes of an artist.

Brown dwarfs are stars in which nuclear reactions could never compensate for energy losses due to radiation. Their spectral class is M - T and Y. Thermonuclear processes can occur in brown dwarfs, but their mass is still too small to start the reaction of converting hydrogen atoms into helium atoms, which is the main condition for the life of a full-fledged star. Brown dwarfs are rather "dim" objects, if that term can be applied to such bodies, and astronomers study them mainly due to the infrared radiation they give off.

Red giants and supergiants are stars with a rather low effective temperature of 2700-4700 ° C, but with a huge luminosity. Their spectrum is characterized by the presence of molecular absorption bands, and the emission maximum falls on the infrared range.

Wolf-Rayet type stars are a class of stars that are characterized by very high temperature and luminosity. Wolf-Rayet stars differ from other hot stars by the presence in the spectrum of broad emission bands of hydrogen, helium, as well as oxygen, carbon, and nitrogen in various degrees of ionization. The final clarity of the origin of Wolf-Rayet type stars has not been achieved. However, it can be argued that in our Galaxy these are the helium remnants of massive stars that shed a significant part of the mass at some stage of their evolution.

T Tauri stars are a class of variable stars named for their prototype T Tauri (final protostars). They can usually be found close to molecular clouds and identified by their (highly irregular) optical variability and chromospheric activity. They belong to the stars of spectral classes F, G, K, M and have a mass less than two solar. Their surface temperature is the same as that of main sequence stars of the same mass, but they have a slightly higher luminosity because their radius is larger. The main source of their energy is gravitational compression.

Bright blue variables, also known as S doradus variables, are very bright blue pulsating hypergiants named after the star S Doradus. They are extremely rare. The bright blue variables can shine a million times brighter than the Sun and can be as massive as 150 solar masses, approaching the theoretical mass limit of a star, making them the brightest, hottest, and most powerful stars in the universe.

White dwarfs are a type of "dying" star. Small stars such as our Sun, which are widely distributed in the Universe, will turn into white dwarfs at the end of their lives - these are small stars (the former cores of stars) with a very high density, which is a million times higher than the density of water. The star is deprived of energy sources and gradually cools down, becoming dark and invisible, but the cooling process can last for billions of years.

Neutron stars - a class of stars, like white dwarfs, are formed after the death of a star with a mass of 8-10 solar masses (stars with a larger mass already form). In this case, the nucleus is compressed until most of the particles turn into neutrons. One of the features of neutron stars is a strong magnetic field. Thanks to it and the rapid rotation acquired by the star due to non-spherical collapse, radio and X-ray sources, called pulsars, are observed in space.

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 placed 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 after detection increased several tens of thousands of times, and after a few months returned to its original value. 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 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

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 emitter (absolutely black body) and completely obeys the classical laws of radiation by 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, there are iron atoms 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 class. 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.

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 "Jewelry 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.