Facts about stars in space. Amazingly beautiful and unusual stars in space

Since ancient times, man has sought to comprehend the unknown, fixing his gaze on the night sky, on which millions of stars are literally scattered. Scientists have always paid serious attention to the study of space and now they have the opportunity, with the help of the most powerful scientific equipment, not only to examine it, but also to do it. unique photos. I invite you to enjoy the amazing photographs of space that they took quite recently and learn some interesting facts.

The beautiful triple nebula NGC 6514 in the constellation Sagittarius. The nebula's name was suggested by William Herschel and means "divided into three petals." The exact distance to it is unknown, but according to various estimates it ranges from 2 to 9 thousand light years. NGC 6514 consists of three main types of nebulae - emission (pinkish), reflective (blue) and absorption (black). (Photo by Máximo Ruiz):

Space Elephant Trunk

The Elephant Trunk Nebula meanders around an emission nebula and a young star cluster in the IC 1396 complex in the constellation Cepheus. The length of the cosmic elephant trunk is more than 20 light years. These dark, whisker-like clouds contain material for the formation of new stars and hide protostars - stars in the final stages of their formation - behind layers of cosmic dust. (Photo by Juan Lozano de Haro):

Ringworld

Hoag's Object is a strange ring-shaped galaxy in the constellation Serpens, named after its discoverer. The distance to Earth is about 600 million light years. At the center of the galaxy is a cluster of relatively old stars yellow. It is surrounded by an almost regular ring of younger stars with a blue tint. The diameter of the galaxy is about 100 thousand light years. Among the hypotheses about the origin are considered a collision of galaxies that occurred several billion years ago. (Photo by R. Lucas (STScI | AURA), Hubble Heritage Team, NASA):

Moon over Andromeda

The large spiral galaxy, the Andromeda Nebula, is located just 2.5 million light years away and is the closest spiral galaxy to our Milky Way. It can be seen with the naked eye as a small blurry speck in the sky. This composite photograph compares the angular size of the Andromeda Nebula and the Moon. (Photo by Adam Block and Tim Puckett):

Io's ever-changing surface

Jupiter's moon Io is the most volcanically active object in the world. solar system. Its surface is constantly changing due to new lava flows. This photograph of the side of Io's moon facing Jupiter is a composite of images taken in 1996 by NASA's Galileo spacecraft. The absence of impact craters is explained by the fact that the entire surface of Io is covered with a layer of volcanic deposits much faster than craters appear. Probable cause Volcanic activity is the changing gravitational tides caused by the huge Jupiter. (Photo by Galileo Project, JPL, NASA):

Cone Nebula

Strange formations can be observed near the Cone Nebula. They arise from the interaction of interstellar dust with light and gas emanating from young stars. The blue glow around the star S Mon is the reflection of the bright star's radiation from surrounding stardust. The star S Mon is located in the open star cluster NGC 2264, located 2,500 light-years from Earth. (Photo by Subaru Telescope (NAOJ) & DSS):

Spiral galaxy NGC 3370

Spiral galaxy NGC 3370 is located about 100 million light-years away in the constellation Leo. It is similar in size and structure to our Milky Way. (Photo by NASA, ESA, Hubble Heritage (STScI | AURA):

Spiral Galaxy M74

This spiral galaxy is one of the photogenic ones. It consists of approximately 100 billion stars and is located at a distance of about 32 million light years from us. Presumably, this galaxy contains a black hole of intermediate mass (that is, significantly larger than stellar masses, but smaller than the black holes at the center of galaxies). (Photo by NASA, ESA, and the Hubble Heritage (STScI | AURA) - ESA | Hubble Collaboration):

Lagoon Nebula

This is a giant interstellar cloud and H II region in the constellation Sagittarius. Located 5,200 light-years away, the Lagoon Nebula is one of only two star-forming nebulae faintly visible to the naked eye at mid-latitudes. Northern Hemisphere. Not far from the center of the Lagoon is a bright area " hourglass"- the result of the turbulent interaction of stellar winds and powerful radiation. (Photo by Ignacio Diaz Bobillo):

Luminous streak in the Pelican Nebula

Clearly visible in the sky, the luminous streak of IC 5067 is part of the large Pelican emission nebula with characteristic shape. The stripe is about 10 light years long and outlines the head and neck of the space pelican. It is located at a distance of about 2,000 light years from us. (Photo by César Blanco González):

thunder cloud

This beautiful photo was taken in southern Alberta, Canada. This is a receding rain cloud, on its near edge there are unusual protrusions characteristic of hummock clouds, and from the far edge of the cloud it's raining. Also read the article “ Rare species clouds." (Photo by Alan Dyer):

Three bright nebulae in Sagittarius

The Lagoon Nebula M8 is to the left of the center of the picture, M20 is a colored nebula to the right. The third nebula, NGC 6559, lies just above M8 and is separated from it by a dark streak of stardust. All of them are located at a distance of about 5 thousand light years from us. (Photo by Tony Hallas):

Galaxy NGC 5195: question mark

The dwarf galaxy NGC 5195 in the constellation Canes Venatici is well known as a small satellite of the spiral galaxy M51, the Whirlpool Galaxy. Together they look like space question mark, in which NGC 5195 is a point. It is located at a distance of about 30 million light years from Earth. (Photo by Hubble Legacy Archive, NASA, ESA):

Amazing expanding crab

This crab nebula, located 6,500 light-years away in the constellation Taurus, is the remnant of a supernova explosion, an expanding cloud of material left after the explosion of a huge star. The nebula is currently about 10 light-years across and is expanding at a speed of approximately 1000 km/s. (Photo by Adam Block, Mt. Lemmon SkyCenter, U. Arizona):

Variable star RS Stern

This is one of the most important stars in the sky. One reason is that she accidentally found herself surrounded by a dazzling reflection nebula. The most bright star in the center is the pulsating RS Stern. It is nearly 10 times more massive than the Sun, 200 times larger, and has an average brightness of 15,000 times the Sun, with RS Puppis changing brightness nearly five times every 41.4 days. RS Puppis lies about a quarter of the way between the Sun and the center of the Milky Way, at a distance of 6,500 light years. years from Earth. (Photo by Hubble Legacy Archive, NASA, ESA):

Ocean planet Gliese 1214b

Exoplanet (super-Earth) in the constellation Ophiuchus. The first ocean planet discovered, it orbits the dim red dwarf star GJ 1214. The planet is close enough to Earth (13 parsecs, or about 40 light years), and because it transits the disk of its star, its atmosphere can be studied in detail using current technology . One year on the planet lasts 36 hours.

The planet's atmosphere consists of thick water vapor with a small admixture of helium and hydrogen. However, given high temperature on the surface of the planet (about 200 degrees Celsius), scientists believe that the water on the planet is in such exotic states as “ hot ice” and “super liquid water”, which are not found on Earth.

The age of the planetary system is estimated at several billion years. The mass of the planet is approximately 6.55 times the mass of the Earth, while at the same time the diameter of the planet is more than 2.5 times greater than that of the Earth. This picture shows how the artist imagines the passage of the super-Earth Gliese 1214b across the disk of its star. (ESO Photo, L. Calçada):

Stardust in the Southern Corona

Here you can see clouds of cosmic dust that are located in the star field near the border of the constellation Corona South. They are less than 500 light-years away and block light from more distant stars in the galaxy Milky Way. In the very center of the image are several reflection nebulae. (Photo by Ignacio Diaz Bobillo):

Galaxy cluster Abell 1689

Abell 1689 is a cluster of galaxies in the constellation Virgo. One of the largest and most massive galaxy clusters known, it acts as a gravitational lens, distorting the light of galaxies behind it. The cluster itself is located at a distance of 2.2 billion light years (670 megaparsecs) from Earth. (Photo by NASA, ESA, Hubble Heritage):

Pleiades

An open cluster in the constellation Taurus, sometimes called the Seven Sisters; one of the closest to Earth and one of the most visible for naked eye star clusters. This is perhaps the most famous star cluster in the sky. The Pleiades star cluster is about 12 light-years in diameter and contains about 1,000 stars. Total weight The stars in the cluster are estimated to be about 800 times the mass of our Sun. (Photo by Roberto Colombari):

Shrimp Nebula

Just south of Antares, in the tail of the nebula-rich constellation Scorpio, lies the emission nebula IC 4628. Hot, massive stars, only a few million years old, illuminate the nebula with invisible light. ultraviolet light. Astronomers call this cosmic cloud the Shrimp Nebula. (ESO Photo):

Constellations are areas of the starry sky. To better navigate the starry sky, ancient people began to identify groups of stars that could be linked into individual figures, similar objects, mythological characters and animals. This system allowed people to organize the night sky, making each part of it easily recognizable. This simplified the study of celestial bodies, helped measure time, apply astronomical knowledge in agriculture and navigate by the stars. The stars that we see in our sky as if in one area can actually be extremely far from each other. In one constellation there may be stars that are in no way connected with each other, both very close and very far from the Earth.

There are 88 official constellations in total. In 1922, the International Astronomical Union officially recognized 88 constellations, 48 of which were described by the ancient Greek astronomer Ptolemy in his star catalog Almagest around 150 BC. There were gaps in Ptolemy's maps, especially regarding the southern sky. Which is quite logical - the constellations described by Ptolemy covered that part of the night sky that is visible from the south of Europe. The remaining gaps began to be filled during the times of the great geographical discoveries. In the 14th century, Dutch scientists Gerard Mercator, Pieter Keyser and Frederic de Houtman added to existing list new constellations, and the Polish astronomer Jan Hevelius and the French Nicolas Louis de Lacaille completed what Ptolemy had started. On the territory of Russia, out of 88 constellations, about 54 can be observed.

Knowledge about the constellations came to us from ancient cultures. Ptolemy compiled a map of the starry sky, but people used knowledge about the constellations long before that. At least in the 8th century BC, when Homer mentioned Bootes, Orion and the Big Dipper in his poems “Iliad” and “Odyssey”, people were already grouping the sky into separate figures. It is believed that the bulk of the knowledge of the ancient Greeks about the constellations came to them from the Egyptians, who, in turn, inherited it from the inhabitants of Ancient Babylon, Sumerians or Akkadians. About thirty constellations were already distinguished by the inhabitants of the late Bronze Age, in 1650−1050. BC, judging by the records on clay tablets of Ancient Mesopotamia. References to constellations can also be found in Hebrew biblical texts. The most remarkable constellation, perhaps, is the constellation Orion: in almost every ancient culture it had its own name and was revered as special. So, in Ancient Egypt he was considered the incarnation of Osiris, and in Ancient Babylon he was called “The Faithful Shepherd of Heaven.” But the most amazing discovery was made in 1972: a piece of mammoth ivory, more than 32 thousand years old, was found in Germany, on which the constellation Orion was carved.

We see different constellations depending on the time of year. Throughout the year, we see different parts of the sky (and different celestial bodies, respectively) because the Earth makes its annual voyage around the Sun. The constellations we see at night are those located behind the Earth on our side of the Sun, because... During the day, behind the bright rays of the Sun, we are unable to see them.

To better understand how this works, imagine that you are riding on a merry-go-round (this is the Earth) with a very bright, blinding light emanating from the center (the Sun). You will not be able to see what is in front of you because of the light, but you will only be able to discern what is outside the carousel. In this case, the picture will constantly change as you ride in a circle. Which constellations you observe in the sky and at what time of year they appear also depends on geographical latitude the beholder.

Constellations travel from east to west, like the Sun. As soon as it begins to get dark, at dusk, the first constellations appear in the eastern part of the sky to pass across the entire sky and disappear with dawn in the western part. Due to the rotation of the Earth around its axis, it seems that the constellations, like the Sun, rise and set. The constellations we just observed on the western horizon just after sunset will soon disappear from our view, to be replaced by constellations that were higher up at sunset just a few weeks ago.

Constellations arising in the east have a diurnal shift of about 1 degree per day: completing a 360-degree trip around the Sun in 365 days gives about the same speed. Exactly one year later, at the same time, the stars will occupy exactly the same position in the sky.

The movement of stars is an illusion and a matter of perspective. The direction in which stars move across the night sky is determined by the rotation of the Earth on its axis and really depends on the perspective and which way the viewer is facing.

Looking north, the constellations appear to move counterclockwise, around a fixed point in the night sky called north pole world located near the North Star. This perception is due to the fact that the earth rotates from west to east, i.e. the earth under your feet moves to the right, and the stars like the Sun, Moon and planets above your head follow the east-west direction, i.e. to the right left. However, if you face south, the stars will appear to move clockwise, from left to right.

Zodiac constellations- these are those through which the Sun moves. The most famous constellations out of the 88 existing ones are the zodiacal ones. These include those through which the center of the Sun passes during the year. It is generally accepted that there are 12 zodiacal constellations in total, although in fact there are 13 of them: from November 30 to December 17, the Sun is in the constellation Ophiuchus, but astrologers do not classify it as a zodiac constellation. All zodiacal constellations are located along the visible annual path of the Sun among the stars, the ecliptic, at an inclination of 23.5 degrees to the equator.

Some constellations have families- These are groups of constellations located in one area of the night sky. As a rule, they assign the names of the most significant constellation. The most “largely populated” constellation is Hercules, which has as many as 19 constellations. Other major families include Ursa Major (10 constellations), Perseus (9) and Orion (9).

Celebrity constellations. The largest constellation is Hydra, which extends over more than 3% of the night sky, while the smallest in area, Southern Cross, occupies only 0.165% of the sky. Centauri boasts the largest number visible stars: 101 stars are included in the famous constellation southern hemisphere sky. To the constellation Canis Major enters the brightest star in our sky, Sirius, whose brilliance is −1.46m. But the constellation called Table Mountain is considered the dimmest and does not contain stars brighter than 5th magnitude. Let us recall that in the numerical characteristic of the brightness of celestial bodies than less value, the brighter the object (the brightness of the Sun, for example, is −26.7m).

Asterism- this is not a constellation. An asterism is a group of stars with an established name, for example, the “Big Dipper,” which is part of the constellation Ursa Major, or “Orion’s Belt,” three stars encircling the figure of Orion in the constellation of the same name. In other words, these are fragments of constellations that have secured a separate name for themselves. The term itself is not strictly scientific, rather simply representing a tribute to tradition.

Looking at the night sky, we see many shining stars. All children think that stars are small and can even fit in the palm of their hand, but adults know that this is not so. But can everyone give a scientific definition?

Let's figure out what a star is from an astronomy point of view.

Star in astronomy

A star in this area means luminous celestial body, which is visible on a cloudless night. Since the stars are several thousand kilometers away from the Earth, we see stars only as luminous points in the sky. In scientific terms, a star is a large ball of gas that emits light and is held in suspension by its own gravity, as well as the pressure generated by thermonuclear fusion reactions.

What are the stars for?

From an astronomy point of view, stars play an important role. For example, the star closest to Earth - the Sun - gives birth to life on Earth, filling it with the necessary energy. The Sun also gives us heat, which gives rise to life. In addition, by heating and evaporating water, the Sun participates in the formation of clouds, which then fall as precipitation.

A cluster of stars emits light. You can read about this in the article.

Types of stars

Stars can be divided into categories according to several criteria:

Colors: blue, white-blue, white, yellow, yellow-white, orange, red.
Brightness changes: novae, supernovae, hypernovae, LBVs (bright blue variables); ULX (ultra-luminous x-ray sources). These stars differ in the speed of color change.
By composition and temperature.

You can learn about the differences between stars and planets in the article.

Other meanings of this word

The word "star" is also called:

Famous and outstanding people in the field of art, science or sports: “Elena Isinbaeva is a star in pole vaulting.” And in figurative meaning a star is an unremarkable and ordinary person: “There goes the local star.”
Geometric figure, which is based on triangular protrusions around the circumference, as well as an object of this shape: a star-shaped candle.
An officer's insignia on shoulder straps, as well as an award order (Order of the Red Star).
Sea animal. More often you can find the phrase " starfish", which means an invertebrate animal of the echinoderm class.

These are the meanings the word “star” can take. Other meanings of words can be found in the section

Units of measurement

Most stellar characteristics are usually expressed in SI, but is also used GHS(For example, luminosity expressed in ergah per second). Mass, luminosity and radius are usually given in relation to our Sun:

To indicate the distance to stars, the following units are used: light year And parsec

Large distances, such as the radius of giant stars or semi-major axis double star systems often expressed using astronomical unit(a.u.) - the average distance between the Earth and the Sun (150 million km).

Physical characteristics

The masses of the vast majority of modern stars range from 0.071 solar masses (75 masses Jupiter) up to 100-150 mass Sun, perhaps the first stars were even more massive. The temperature in the depths of stars reaches 10-12 million.

Distance

There are many ways to determine the distance to a star. But the most accurate and the basis for all other methods is the measurement method parallaxes stars First to measure the distance to a star Vega Russian astronomer Vasily Yakovlevich Struve in 1837. Determining parallaxes from the Earth's surface allows you to measure distances up to 100 parsec, and from special astrometric satellites, such as Hipparcos, - up to 1000 pcs. If the star is part of a star cluster, then we will not be much mistaken if we take the distance to the star equal to the distance to the accumulation. If the star belongs to the class Cepheid, then the distance can be found from the relationship between the pulsation period and the absolute magnitude. Basically, it is used to determine the distance to distant stars. photometry.

Weight

The mass of a star can be reliably determined only if it is a component double star. In this case, the mass can be calculated using the generalized Kepler's third law. But even so, the error estimate ranges from 20% to 60% and, to a large extent, depends on the error in determining the distance to the star. In all other cases, it is necessary to determine the mass by indirect signs, for example, the dependence of the luminosity and mass of the star. .

Chemical composition

Extremely important characteristic is hers chemical composition, both from the point of view of the star and from the point of view of the observer. And although the proportion of elements heavier than helium is no more than a few percent, they play an important role in the life of a star. Thanks to them, nuclear reactions can slow down or speed up, and this will affect both the brightness of the star, its color, and its lifespan. So the greater the metallicity of a massive star, the smaller the supernova remnant will be. An observer, knowing the chemical composition of a star, can fairly confidently predict the time of star formation. Since all those tragic changes that occur with a star throughout its life do not touch the surface of the star. This is always so few massive and moderately massive stars, and almost always for massive stars.

Structure of stars

The emergence and evolution of stars

A star begins its life as a cold, tenuous cloud of interstellar gas, compressed by its own gravity. When compressed, the energy gravity turns into heat, and the temperature of the gas globule increases. When the temperature in the core reaches several million Kelvin, begin thermonuclear reactions and the compression stops. The star remains in this state for most of its life, being at main sequence Hertzsprung-Russell diagrams, until the fuel reserves in its core run out. When all the hydrogen in the center of the star turns into helium, thermonuclear burning of hydrogen continues at the periphery of the helium core.

During this period, the structure of the star begins to change noticeably. Its luminosity increases, the outer layers expand, and the inner layers, on the contrary, contract. And for the time being, the brightness of the star also decreases. The surface temperature decreases - the star becomes red giant. A star spends significantly less time on the giant branch than on the main sequence. When the mass of its isothermal helium core becomes significant, it cannot withstand own weight and begins to shrink; the increasing temperature stimulates the thermonuclear transformation of helium into heavier elements.

The vast majority of stars, and Sun including finishing evolution by contracting until the pressure degenerate electrons won't balance gravity. In this state, when the size of the star decreases by a hundred times, and the density becomes a million times higher than the density water, the star is called a white dwarf. It is deprived of energy sources and, gradually cooling down, becomes dark and invisible.

In stars more massive than the Sun, the pressure of degenerate electrons cannot contain the compression 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 its density is 280 trillion. times the density of water. Such an object is called neutron star; its equilibrium is maintained by the pressure of the degenerate neutron matter.

Scheme of the evolution of single stars

small masses 0.08M sun	moderate masses 0.5M sun		massive stars 8M sun
	0.5M sun	3M sun	8M sun	M * >10M sun
burning of hydrogen in the core
helium white dwarfs	degenerate Not the core	non-degenerate Not the core
	helium flash
	quiet combustion of helium in the core
	CO white dwarf		degenerate CO core	non-degenerate CO core
			carbon det.	combustion of carbon in the core. CO to Fe
			combustion of carbon in the core. C to O, Ne, Si, Fe, Ni..
			O,Ne,Mg... white dwarf or neutron star	black hole

Scheme of the evolution of single stars. According to V. A. Baturin and I. V. Mironova

Duration of stellar evolution

Classification of stars

Stars are classified by luminosity, mass, temperature surface, chemical composition, spectrum features ( spectral class) and multiplicity.

Multiple stars

Stellar systems can be single and multiple: double, triple and higher multiplicity. If a system includes more than ten stars, it is customary to call it star cluster. Double (multiples) stars are very common. According to some estimates, more than 70% of the stars in the galaxy are multiples. So, among the 32 stars closest to Earth, 12 are multiple, of which 10 are double, including the brightest visually observable star Sirius. In the vicinity of 20 parsecs from the Solar System there are more than 3000 stars, about half are double stars of all types

Star designations

Beautifully illustrated Uranometry(Uranometria,) German astronomer I. Bayer(-), where shown constellations and the legendary figures associated with their names, the stars were first designated by letters Greek alphabet approximately in descending order of their brilliance: α is the brightest star in the constellation, β is the second brightest, etc. When there were not enough letters of the Greek alphabet, Bayer used Latin. The full designation of the star consisted of the mentioned letter and the Latin name of the constellation. For example, Sirius- the brightest star in the constellation Canis Major(Canis Major), therefore it is designated as α Canis Majoris, or abbreviated α CMa; Algol is the second brightest star in Perseus denoted as β Persei, or β Per. Bayer, however, did not always follow the rule he introduced, and there are a large number of exceptions to Bayer's notation.