Why are stars different colors?

Stars are the main objects of the Universe visible to us. The cosmic world is extraordinary and diverse. The topic of universal luminaries is inexhaustible. The sun was created to shine during the day, and the stars were created to illuminate man’s earthly path at night. This article will discuss how the light we see, emanating from amazing celestial bodies, is formed.

Origin

The birth of a star, as well as its extinction, can be visually seen in the night sky. Astronomers have been observing these phenomena for a long time and have already made many discoveries. All of them are described in special scientific literature. Stars are luminous balls of fire of incredibly large sizes. But why do they glow, flicker and shimmer in different colors?

These celestial bodies are born from a diffuse gas and dust environment, resulting from gravitational compression in denser layers, plus the influence of their own gravity. The composition of the interstellar medium is mainly gas (hydrogen and helium) with a dust of solid mineral particles. Our main luminary is a star called the Sun. Without it, life for all things on our planet is impossible. Interestingly, many stars are much larger than the Sun. Why don’t we feel their impact and can calmly exist without them?

Our source of heat and light is located close to the Earth. Therefore, for us we can significantly feel its light and warmth. The stars are hotter than the Sun and larger in size, but they are at such great distances that we can only observe their light, and then only at night.

They seem to be just flickering dots in the night sky. Why don't we see them during the day? Starlight is like the rays from a flashlight, which you can barely see during the day, but at night you can’t do without it - it illuminates the road well.

When is it brightest and why do the stars glow in the night sky?

August is the best month for stargazing. At this time of year the evenings are dark and the air is clear. It feels like you can reach the sky with your hand. Children, looking up to the sky, always wonder: “Why do the stars glow and where do they fall?” The fact is that in August people often watch starfalls. This is an extraordinary sight that attracts our eyes and souls. There is a belief that when you see a shooting star, you need to make a wish that will certainly come true.

However, what's interesting is that it's not actually a star falling, but a meteor burning up. Be that as it may, this phenomenon is very beautiful! Times pass, generations of people replace each other, but the sky is still the same - beautiful and mysterious. Just like us, our ancestors looked at it, guessed the figures of various mythological characters and objects in star clusters, made wishes and dreamed.

How does light appear?

Space objects called stars emit incredibly large amounts of thermal energy. Energy emissions are accompanied by strong radiation of light, a certain part of which reaches our planet, and we have the opportunity to observe it. This is a short answer to the question: “Why do the stars shine in the sky, and do all heavenly bodies belong to them?” For example, the Moon is a satellite of the Earth, and Venus is a planet of the solar system. We do not see their own light, but only its reflection. Stars themselves are a source of light radiation resulting from the release of energy.

Some celestial objects have white light, while others have blue or orange light. There are also those that shimmer in different shades. What is this connected with and why do stars glow in different colors? The fact is that they are huge balls consisting of gases heated to very high temperatures. As this temperature fluctuates, stars have different luminosities: the hottest are blue, followed by white, even cooler yellow, then orange and red.

Flicker

Many people are interested: why do stars glow at night and their light flickers? First of all, they don't flicker. It only seems to us. The fact is that starlight passes through the thickness of the earth's atmosphere. A ray of light, traveling such long distances, undergoes a large number of refractions and changes. To us, these refractions look like flickers.

A star has its own life cycle. At different stages of this cycle it glows differently. When its lifetime comes to an end, it begins to gradually turn into a red dwarf and cools down. The radiation of the dying star pulsates. This creates the impression of flickering (blinking). During the day, the light from the star does not disappear anywhere, but it is overshadowed by the too bright and close sunshine. Therefore, at night we see them due to the fact that there are no rays of the Sun.

We never think that perhaps there is some other life besides our planet, besides our solar system. Perhaps there is life on one of the planets orbiting a blue or white or red, or maybe a yellow star. Perhaps there is another planet like this, on which the same people live, but we still don’t know anything about it. Our satellites and telescopes have discovered a number of planets that may have life, but these planets are tens of thousands and even millions of light years away.

Blue stragglers are stars that are blue in color.

Stars located in globular star clusters, whose temperature is higher than that of ordinary stars, and whose 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 stars that arose in the same period of time are expected to be located in a well-defined region of the Hertzsprung-Russell diagram. In this case, the only factor that affects the exact location of the star is its initial mass. The frequent appearance of blue stragglers outside the above curve may confirm the existence of such a thing as anomalous stellar evolution.

Experts trying to explain the nature of their occurrence have put forward several theories. The most likely of them indicates that these blue stars were double in the past, after which they began to undergo or are now undergoing a merger process. 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 this theory could somehow be proven correct, the theory of stellar evolution would be free of the problem of blue stragglers. The resulting star would have a larger amount of hydrogen, which would behave similarly to a young star. There are facts that support this theory. Observations have shown that stragglers are most often found in the central regions of globular clusters. As a result of the predominant number of unit-volume stars there, close passages or collisions become more likely.

To test this hypothesis, it is necessary to study the pulsation of blue stragglers, because There may be some differences between the asteroseismological properties of merged stars and normally pulsating variables. It is worth noting that measuring pulsations is quite difficult. 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 object V1309, the brightness of which, after discovery, increased several tens of thousands of times, and after several months returned to its original value. As a result of 6 years of observations, scientists came to the conclusion that this object is two stars whose orbital period around each other is 1.4 days. These facts led scientists to believe that in August 2008, the process of merging 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 higher than the rotation speed of the Sun. According to the hypothesis, their mass is 2-3 times greater than the mass of other stars that are located in the cluster. Also, through research, it was found that if blue stars are located close to any other stars, then the latter will have a lower percentage of oxygen and carbon than their neighbors. Presumably, stars pull these substances from other stars moving in their orbit, as a result of which their brightness and temperature increase. In “robbed” stars, places are discovered where the process of transformation of the original carbon into other elements took place.

Names of blue stars - examples

Rigel, Gamma Paralis, Alpha Giraffe, Zeta Orionis, Tau Canis Majoris, Zeta Puppis

White stars are white stars

Friedrich Bessel, who headed the Königsberg Observatory, made an interesting discovery in 1844. The scientist noticed the slightest deviation of the brightest star in the sky, Sirius, from its trajectory across 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 adequate support from other scientists, because No one was able to detect the satellite, although its mass 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 its 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/cm3, while the density of Sirius itself is approximately 0.25 g/cm3, and that of the Sun is 1.4 g/cm3). 55 years later (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 Aquila (visible in summer and autumn), Sirius, Castor.

Yellow stars - yellow stars

Yellow dwarfs are usually called small main sequence stars whose mass 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 hydrogen to helium.

The surface of such stars heats up to a temperature of 5-6 thousand Kelvin, and their spectral classes range 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 transforms 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 located 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 Alhita, Dabikh, Toliman, Khara, 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 0th magnitude, but at the same time its brightness is the highest among all yellow dwarfs. This star is located in the constellation Centaurus, and it is also part of a complex system that 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, spectral class G has HD82943, 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 absorbed them all.

Names of yellow stars - examples

Toliman, star HD 82943, Hara, Dabih, Alhita

Red stars are red stars

If at least once in your life you have seen through the lens of your telescope red stars in the sky that were burning against a black background, then remembering this moment will help you more clearly imagine what will be written about in this article. If you have never seen such stars before, be sure to try to find them next time.

If you set out to compile a list of the brightest red stars in the sky, which can be easily found even with an amateur telescope, you will find that they are all carbon stars. The first red stars were discovered back in 1868. The temperature of such red giants is low, in addition, their outer layers are filled with huge amounts of carbon. If previously similar stars made up two spectral classes - R and N, now scientists have defined them into one general class - C. Each spectral class has subclasses - from 9 to 0. Moreover, class C0 means that the star has a high temperature, but less red than C9 class 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 this list, the most famous of which is m Cephei. William Herschel became interested in its unusual red color and dubbed it “pomegranate.” Such stars are characterized by irregular changes in luminosity, which can last from a couple of tens to several hundred days. Such variable stars belong to class M (cool stars with surface temperatures from 2400 to 3800 K).

Considering the fact that all the stars in the rating are variables, it is necessary to bring some clarity to the notation. It is generally accepted that red stars have a name that consists of two components - a letter of the Latin alphabet and the name of a variable constellation (for example, T Hare). The first variable discovered in a given 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 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 the Uranometria 2000.0 atlas among astronomy enthusiasts, the last column of the rating displays the search chart number 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 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 the number of days, but objects that do not have the correct period are displayed as Irr.

Finding a carbon star does not require much skill; it is enough that the capabilities of your telescope are enough to see it. Even if its size is small, its bright red color should attract your attention. Therefore, you should not be upset if you cannot detect them immediately. 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 shades in such stars. To begin with, the rating has a list of the six brightest red stars, which, once found, you can fully enjoy their beauty.

Names of red stars - examples

Star color differences

There is a huge variety of stars with indescribable color shades. As a result, even one constellation received the name “Jewel Box”, the basis of which is made up of blue and sapphire stars, and in its very center is a brightly shining orange star. If we consider the Sun, it has a pale yellow color.

A direct factor influencing the difference in color between stars is their surface temperature. This is explained simply. Light by its nature is radiation in the form of waves. The wavelength is the distance between its crests and is very small. To imagine it, you need to divide 1 cm into 100 thousand identical parts. Several of these particles will make up the wavelength of light.

Considering that this number turns out to be quite small, every, even the most insignificant, change in it will be the reason why the picture we observe will change. After all, our vision perceives different wavelengths of light as different colors. For example, blue has waves whose length is 1.5 times shorter than that of red.

Also, almost every one of us knows that temperature can have a very direct effect on the color of bodies. For example, you can take any metal object and put it on the fire. It will turn red while heating. If the temperature of the fire increased significantly, the color of the object would 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 of around 5.5 thousand 0 C, it is a typical example of yellow stars. But the hottest blue stars can heat up to 33 thousand degrees.

Color and temperature were linked by scientists using physical laws. How the temperature of a body is directly proportional to its radiation and inversely proportional to the wavelength. Blue waves have shorter wavelengths compared to red. Hot gases emit photons, the energy of which is directly proportional to temperature and inversely proportional to wavelength. That is why the hottest stars are characterized by a blue-blue emission range.

Since nuclear fuel on stars is not unlimited, it tends to be consumed, which leads to the cooling of 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. This is what a device called a spectrograph is used for. Scientists pass through it the light emitted by stars, as a result of which it is possible to spectrally analyze almost any star.

In addition, using the color of a star, you can determine its age, because mathematical formulas make it possible to use spectral analysis to determine the temperature of a star, from which it is easy to calculate its age.

Video secrets of the stars watch online

Stars do not reflect light, as planets and their satellites do, but emit it. And evenly and constantly. And the blinking visible on Earth is possibly caused by the presence of various microparticles in space, which, when entering the light beam, interrupt it.

The brightest star, from the point of view of earthlings

From school we know that the Sun is a star. From our planet, this is, and by the standards of the Universe, it is slightly less than average both in size and brightness. A huge number of stars are larger than the Sun, but there are much fewer of them.

Star gradation

Ancient Greek astronomers began dividing celestial bodies by size. By the concept of “magnitude”, both then and now, they mean the brightness of the star’s glow, and not its physical size.

Stars also differ in the length of their radiation. Based on the wave spectrum, and it is indeed diverse, astronomers can tell about the chemical composition of the body, temperature and even distance.

Scientists argue

The debate on the question “why do the stars shine” has lasted for decades. There is still no consensus. It is difficult even for nuclear physicists to believe that the reactions occurring in a stellar body can release such a huge amount of energy without stopping.

The problem of what passes through the stars has occupied scientists for a very long time. Astronomers, physicists, and chemists have attempted to figure out what triggers the eruption of thermal energy, which is accompanied by bright radiation.

Chemists believe that the light from a distant star is the result of an exothermic reaction. It ends with the release of a significant amount of heat. Physicists say that chemical reactions cannot take place in the body of a star. For none of them is capable of going non-stop for billions of years.

The answer to the question “why do stars shine” became a little closer after Mendeleev’s discovery of the table of elements. Now chemical reactions have begun to be viewed in a completely new way. As a result of the experiments, new radioactive elements were obtained, and the theory of radioactive decay becomes the number one version in the endless debate about the glow of stars.

Modern hypothesis

The light of a distant star did not allow Svante Arrhenius, a Swedish scientist, to “sleep”. At the beginning of the last century, he turned the idea of radiation of heat by stars, developing the concept. It consisted of the following. The main source of energy in the body of a star is hydrogen atoms, which constantly participate in chemical reactions with each other, forming helium, which is much heavier than its predecessor. Transformation processes occur due to gas pressure of high density and a temperature that is wild for our understanding (15,000,000°C).

The hypothesis was liked by many scientists. The conclusion was clear: the stars in the night sky glow because a fusion reaction occurs inside and the energy released during this process is more than enough. It also became clear that the combination of hydrogen can proceed non-stop for many billions of years in a row.

So why do stars shine? The energy that is released in the core is transferred to the outer gas shell and radiation visible to us occurs. Today, scientists are almost sure that the “road” of the beam from the core to the shell takes more than a hundred thousand years. The beam from the star also takes quite a long time to reach the Earth. If radiation from the Sun reaches the Earth in eight minutes, the brighter stars - Proxima Centauri - in almost five years, then the light of the rest can travel for tens and hundreds of years.

One more “why”

Why stars emit light is now clear. Why is it flickering? The glow coming from the star is actually even. This is due to gravity, which pulls the gas expelled by the star back. The flickering of a star is a kind of error. The human eye sees a star through several layers of air, which is in constant motion. A star ray passing through these layers appears to flicker.

Since the atmosphere is constantly moving, hot and cold air flows, passing under each other, form turbulence. This causes the light beam to bend. also changes. The reason is the uneven concentration of the beam reaching us. The star pattern itself is shifting. This phenomenon is caused by gusts of wind passing through the atmosphere, for example.

Multicolored stars

In cloudless weather, the night sky pleases the eye with its bright colors. Arcturus also has a rich orange color, but Antares and Betelgeuse are soft red. Sirius and Vega are milky white, with a blue tint - Regulus and Spica. The famous giants - Alpha Centauri and Capella - are juicy yellow.

Why do stars shine differently? The color of a star depends on its internal temperature. The “coldest” ones are red. On their surface there is only 4,000°C. with surface heating up to 30,000°C - are considered the hottest.

Cosmonauts say that in reality the stars shine evenly and brightly, and they only wink at earthlings...

Karpov Dmitry

This is a research work by a 1st grade student of Municipal Educational Institution 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 observation results, 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 red, then yellow and, finally, white as the temperature increases. Same with the stars. Reds are the coldest, and whites (or even blues!) are the hottest. Heavy stars are hot and white, light, non-massive stars are red and relatively cool. The color of a star can also be used to determine its age. Young stars are the hottest. They shine with white and blue light. Old, cooling stars emit red light. And middle-aged stars glow with yellow light. The energy emitted by stars is so enormous that we can see them at those distant 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 and mass.

3. We can see stars thanks to the enormous energy they emit.

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