Stars are large celestial bodies of hot plasma, the dimensions of which can amaze the most inquisitive reader. Ready to evolve?
It should be noted right away that the rating was compiled taking into account those giants that are already known to mankind. It is possible that somewhere in outer space there are stars of even larger dimensions, but it is located at a distance of many light years, and modern equipment is simply not enough to detect and analyze them. It is also worth adding that the largest stars will eventually cease to be such, because they belong to the class of variables. Well, do not forget about the probable errors of astrologers. So...
Top 10 biggest stars in the universe
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Opens the rating of the largest stars in the Betelgeuse Galaxy, the size of which exceeds the radius of the sun by 1190 times. It is located approximately 640 light years from Earth. Comparing with other stars, we can say that at a relatively small distance from our planet. The red-colored giant in the next few hundred years can turn into a supernova. In this case, its dimensions will increase significantly. For justified reasons, the star Betelgeuse, ranking last in this ranking, is the most interesting!
RW
An amazing star, attracting with an unusual glow color. Its size exceeds the dimensions of the sun from 1200 to 1600 solar radii. Unfortunately, we cannot say exactly how powerful and bright this star is, because it is located far from our planet. Regarding the history of the emergence and distance of RW, leading astrologers from different countries have been arguing for many years. Everything is due to the fact that in the constellation it regularly changes. Over time, it may disappear altogether. But it is still in the top of the largest celestial bodies.
Next in the ranking of the largest known stars is KW Sagittarius. According to ancient Greek legend, she appeared after the death of Perseus and Andromeda. This suggests that it was possible to detect this constellation long before our appearance. But unlike our ancestors, we know about more reliable data. It is known that the size of the stars exceeds the Sun by 1470 times. However, it is relatively close to our planet. KW is a bright star that changes its temperature over time.
At present, it is known for certain that the size of this large star exceeds the size of the Sun by at least 1430 times, but it is difficult to get an accurate result, because it is located 5 thousand light years from the planet. Even 13 years ago, American scientists cite completely different data. At that time, it was believed that KY Cygnus had a radius that raised the Sun by 2850 times. Now we have more reliable dimensions relative to this celestial body, which, for sure, are more accurate. Based on the name, you understand that the star is located in the constellation Cygnus.
A very large star included in the constellation Cepheus is V354, the size of which exceeds the Sun by 1530 times. At the same time, the celestial body is relatively close to our planet, only 9 thousand light years away. It does not differ in special brightness and temperature against the background of other unique stars. However, it belongs to the number of variable luminaries, therefore, the dimensions may vary. It is likely that Cepheus will not last long at this position in the V354 rating. It will most likely decrease in size over time.
A few years ago, it was believed that this red giant could become a competitor for VY Canis Major. Moreover, some experts conditionally considered WHO G64 the largest known star in our Universe. Today, in an age of rapid development of technology, astrologers have managed to obtain more reliable data. It is now known that the radius of the Dorado is only 1550 times the size of the Sun. That's how huge errors are allowed in the field of astronomy. However, the incident is easily explained by distance. The star is outside the Milky Way. Namely, in a dwarf galaxy called the Huge Magellanic Cloud.
V838
One of the most unusual stars in the universe, located in the constellation of the Unicorn. It is located approximately 20 thousand light years from our planet. Even the fact that our specialists managed to find it is surprising. Luminary V838 is even larger than that of Mu Cephei. It is quite difficult to make accurate calculations regarding the dimensions, due to the huge distance from the Earth. Speaking of approximate size data, they range from 1170 to 1900 solar radii.
There are many amazing stars in the constellation Cepheus, and Mu Cephei is considered a confirmation of this. One of the largest stars exceeds the size of the Sun by 1660 times. The supergiant is considered one of the brightest in the Milky Way. Approximately 37,000 times more powerful than the illumination of the star most known to us, that is, the Sun. Unfortunately, we cannot say unequivocally at what distance from our planet Mu Cephei is located.
For many centuries, millions of human eyes, with the onset of night, direct their gaze upward - towards the mysterious lights in the sky - stars in our universe. Ancient people saw various figures of animals and people in clusters of stars, and each of them created their own history. Later, such clusters began to be called constellations. To date, astronomers identify 88 constellations that divide the starry sky into certain areas, by which you can navigate and determine the location of the stars. In our Universe, the most numerous objects accessible to the human eye are precisely the stars. They are the source of light and energy for the entire solar system. They also create the heavy elements necessary for the origin of life. And without the stars of the Universe there would be no life, because the Sun gives its energy to almost all living beings on Earth. It warms the surface of our planet, thus creating a warm, full of life oasis among the permafrost of space. The degree of brightness of a star in the universe is determined by its size.
Do you know the biggest star in the entire universe?
The star VY Canis Majoris, located in the constellation Canis Major, is the largest representative of the stellar world. It is currently the largest star in the universe. The star is located 5 thousand light years from the solar system. The diameter of the star is 2.9 billion km.
But not all stars in the universe are so huge. There are also so-called dwarf stars.
Comparative sizes of stars
Astronomers evaluate the magnitude of stars on a scale according to which the brighter the star, the lower its number. Each subsequent number corresponds to a star ten times less bright than the previous one. The brightest star in the night sky in the universe is Sirius. Its apparent magnitude is -1.46, which means it is 15 times brighter than a zero-magnitude star. Stars with a magnitude of 8 or more cannot be seen with the naked eye. Stars are also divided by color into spectral classes that indicate their temperature. There are the following classes of stars in the Universe: O, B, A, F, G, K, and M. Class O corresponds to the hottest stars in the Universe - blue. The coldest stars belong to the class M, their color is red.
| Class | Temperature, K | true color | Visible color | Main features |
|---|---|---|---|---|
| O | 30 000—60 000 | blue | blue | Weak lines of neutral hydrogen, helium, ionized helium, multiply ionized Si, C, N. |
| B | 10 000—30 000 | white-blue | white-blue and white | Absorption lines for helium and hydrogen. Weak H and K Ca II lines. |
| A | 7500—10 000 | white | white | Strong Balmer series, the H and K Ca II lines increase towards the F class. Metal lines also begin to appear closer to the F class. |
| F | 6000—7500 | yellow-white | white | The H and K lines of Ca II, metal lines are strong. The hydrogen lines begin to weaken. The Ca I line appears. The G band formed by the Fe, Ca, and Ti lines appears and intensifies. |
| G | 5000—6000 | yellow | yellow | The H and K lines of Ca II are intense. Ca I line and numerous metal lines. The hydrogen lines continue to weaken, and bands of CH and CN molecules appear. |
| K | 3500—5000 | orange | yellowish orange | The metal lines and the G band are intense. Hydrogen lines are almost invisible. TiO absorption bands appear. |
| M | 2000—3500 | red | orange red | The bands of TiO and other molecules are intense. The G band is weakening. Metal lines are still visible. |
Contrary to popular belief, it is worth noting that the stars of the universe do not actually twinkle. This is just an optical illusion - the result of atmospheric interference. A similar effect can be observed on a hot summer day, looking at hot asphalt or concrete. The hot air rises, and it seems as if you are looking through trembling glass. The same process causes the illusion of stellar twinkling. The closer a star is to Earth, the more it will "flicker" because its light travels through the denser layers of the atmosphere.
Nuclear Center of the stars of the Universe
A star in the universe is a giant nuclear focus. The nuclear reaction inside it converts hydrogen into helium through the process of fusion, so the star acquires its energy. Hydrogen atomic nuclei with one proton combine to form helium atoms with two protons. The nucleus of an ordinary hydrogen atom has only one proton. The two isotopes of hydrogen also contain one proton, but also have neutrons. Deuterium has one neutron, while Tritium has two. Deep inside a star, a deuterium atom combines with a tritium atom to form a helium atom and a free neutron. As a result of this long process, a huge amount of energy is released.
For main sequence stars, the main source of energy is nuclear reactions involving hydrogen: the proton-proton cycle, characteristic of stars with a mass near the solar one, and the CNO cycle, which occurs only in massive stars and only in the presence of carbon in their composition. In the later stages of a star's life, nuclear reactions can also take place with heavier elements, up to iron.
| Proton-proton cycle | CNO cycle | |
| Main chains |
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When a star's hydrogen supply is depleted, it begins to convert helium into oxygen and carbon. If the star is massive enough, the transformation process will continue until carbon and oxygen form neon, sodium, magnesium, sulfur, and silicon. As a result, these elements are converted into calcium, iron, nickel, chromium and copper until the core is completely metal. As soon as this happens, the nuclear reaction will stop, since the melting point of iron is too high. The internal gravitational pressure becomes higher than the external pressure of the nuclear reaction and, eventually, the star collapses. Further development of events depends on the initial mass of the star.
Types of stars in the universe
The main sequence is the period of existence of the stars of the Universe, during which a nuclear reaction takes place inside it, which is the longest segment of the life of a star. Our Sun is currently in this period. At this time, the star undergoes minor fluctuations in brightness and temperature. The duration of this period depends on the mass of the star. In large massive stars it is shorter, while in small ones it is longer. Very large stars have enough internal fuel for several hundred thousand years, while small stars like the Sun will shine for billions of years. The largest stars turn into blue giants during the main sequence.
Types of stars in the universe |
|
| red giant- This is a large reddish or orange star. It represents the late stage of the cycle, when the supply of hydrogen comes to an end and helium begins to be converted into other elements. An increase in the internal temperature of the core leads to the collapse of the star. The outer surface of the star expands and cools, causing the star to turn red. Red giants are very large. Their size is a hundred times larger than ordinary stars. The largest of the giants turn into red supergiants. A star called Betelgeuse in the constellation Orion is the most striking example of a red supergiant. |  |
| white dwarf- this is what remains of an ordinary star after it passes the stage of a red giant. When a star runs out of fuel, it can release some of its matter into space, forming a planetary nebula. What remains is the dead core. A nuclear reaction is not possible in it. It shines due to its remaining energy, but sooner or later it ends, and then the core cools down, turning into a black dwarf. White dwarfs are very dense. They are no larger than the Earth in size, but their mass can be compared with the mass of the Sun. These are incredibly hot stars, reaching temperatures of 100,000 degrees or more. |  |
| brown dwarf also called a substar. During their life cycle, some protostars never reach critical mass to start nuclear processes. If the mass of a protostar is only 1/10 of the mass of the Sun, its radiance will be short-lived, after which it quickly fades. What remains is the brown dwarf. It's a massive ball of gas, too big to be a planet and too small to be a star. It is smaller than the Sun, but several times larger than Jupiter. Brown dwarfs emit neither light nor heat. This is just a dark clot of matter that exists in the vastness of the universe. |  |
| cepheid is a star with a variable luminosity, the pulsation cycle of which varies from a few seconds to several years, depending on the variety of the variable star. Cepheids usually change their luminosity at the beginning of life and at its end. They are internal (changing luminosity due to processes inside the star) and external, changing brightness due to external factors, such as the influence of the orbit of the nearest star. This is also called a dual system. |  |
| Many stars in the universe are part of large star systems. double stars- a system of two stars, gravitationally connected to each other. They revolve in closed orbits around a single center of mass. It has been proven that half of all the stars in our galaxy have a pair. Visually, paired stars look like two separate stars. They can be determined by the shift of the spectrum lines (Doppler effect). In eclipsing binaries, stars periodically outshine each other because their orbits are located at a small angle to the line of sight. |  |
Life Cycle of the Stars of the Universe
A star in the universe begins its life as a cloud of dust and gas called a nebula. The gravity of a nearby star or the blast wave of a supernova can cause the nebula to collapse. The elements of the gas cloud coalesce into a dense region called a protostar. As a result of the subsequent compression, the protostar heats up. As a result, it reaches a critical mass, and the nuclear process begins; gradually the star goes through all the phases of its existence. The first (nuclear) stage of a star's life is the longest and most stable. The lifespan of a star depends on its size. Large stars consume their life fuel faster. Their life cycle can last no more than a few hundred thousand years. But small stars live for many billions of years, as they spend their energy more slowly.
But be that as it may, sooner or later, stellar fuel runs out, and then a small star turns into a red giant, and a large star into a red supergiant. This phase will last until the fuel is completely used up. At this critical moment, the internal pressure of the nuclear reaction will weaken and no longer be able to balance the force of gravity, and, as a result, the star will collapse. Then the small stars of the Universe, as a rule, reincarnate into a planetary nebula with a bright shining core, called a white dwarf. Over time, it cools down, turning into a dark clot of matter - a black dwarf.
For big stars, things happen a little differently. During the collapse, they release an incredible amount of energy, and a powerful explosion gives birth to a supernova. If its magnitude is 1.4 the magnitude of the Sun, then, unfortunately, the core will not be able to maintain its existence and, after the next collapse, the supernova will become a neutron star. The internal matter of the star will shrink to such an extent that the atoms form a dense shell consisting of neutrons. If the stellar magnitude is three times greater than the solar value, then the collapse will simply destroy it, wipe it off the face of the Universe. All that remains of it is a site of strong gravity, nicknamed a black hole.
The nebula left behind by the star of the universe can expand over millions of years. In the end, it will be affected by the gravity of a nearby or the blast wave of a supernova and everything will repeat itself again. This process will take place throughout the universe - an endless cycle of life, death and rebirth. The result of this stellar evolution is the formation of heavy elements necessary for life. Our solar system came from the second or third generation of the nebula, and because of this, there are heavy elements on Earth and other planets. And this means that in each of us there are particles of stars. All the atoms of our body were born in an atomic hearth or as a result of a devastating supernova explosion.
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10
10th place - AH Scorpio
The tenth line of the largest stars in our Universe is occupied by a red supergiant, located in the constellation Scorpio. The equatorial radius of this star is 1287 - 1535 radius of our sun. It is located approximately 12,000 light years from Earth.
9
9th place - KY Lebedya
The ninth place is occupied by a star located in the constellation Cygnus at a distance of about 5 thousand light years from Earth. The equatorial radius of this star is 1420 solar radii. However, its mass exceeds the mass of the Sun by only 25 times. Shines KY Cygnus about a million times brighter than the Sun.
8
8th place - VV Cepheus A
VV Cephei is an eclipsing Algol-type binary star in the constellation Cepheus, about 5,000 light-years from Earth. It is the second largest star in the Milky Way Galaxy (after VY Canis Major). The equatorial radius of this star is 1050 - 1900 solar radii.
7
7th place - VY Big Dog
The largest star in our galaxy. The radius of the star lies in the range 1300 - 1540 radii of the sun. It would take light 8 hours to go around a star in a circle. Studies have shown that the star is unstable. Astronomers predict that VY Canis Major will explode as a hypernova in the next 100,000 years. Theoretically, a hypernova explosion would cause gamma-ray bursts that could damage the contents of the local part of the universe, destroying any cellular life within a radius of several light years, however, the hypergiant is not close enough to Earth to pose a threat (approximately 4 thousand light years).
6
6th place - VX Sagittarius
Giant pulsating variable star. Its volume, as well as the temperature, change periodically. According to astronomers, the equatorial radius of this star is 1520 radii of the sun. The star got its name from the name of the constellation in which it is located. The manifestations of a star due to its pulsation resemble the biorhythms of the human heart.
5
5th place - Westerland 1-26
The fifth line is occupied by a red supergiant, the radius of this star lies in the range 1520 - 1540 solar radii. It is located 11,500 light years from Earth. If Westerland 1-26 were at the center of the solar system, its photosphere would encompass the orbit of Jupiter. For example, the typical length of the photosphere in depth for the Sun is 300 km.
4
4th place - WOH G64
WOH G64 is a red supergiant located in the constellation Dorado. Located in the neighboring galaxy Large Magellanic Cloud. The distance to the solar system is approximately 163,000 light years. The radius of the star lies in the range 1540 - 1730 solar radii. The star will end its existence and become a supernova in a few thousand or tens of thousands of years.
3
3rd place - RW Cepheus
Bronze goes to RW Cephei. The red supergiant is located at a distance of 2739 light years from us. The equatorial radius of this star is 1636 solar radii.
2
2nd place - NML Lebedya
The second line of the largest stars in the Universe is occupied by a red hypergiant in the constellation Cygnus. The radius of the star is about 1650 solar radii. The distance to it is estimated at about 5300 light years. As part of the star, astronomers discovered substances such as water, carbon monoxide, hydrogen sulfide, sulfur oxide.
1
1st place - UY Shield
The largest star in our Universe at the moment is a hypergiant in the constellation Scutum. It is located at a distance of 9500 light years from the Sun. The equatorial radius of the star is 1708 radius of our sun. The luminosity of the star is approximately 120,000 times greater than the luminosity of the Sun in the visible part of the spectrum, the brightness would be much higher if there were not a large accumulation of gas and dust around the star.
Historical site of Bagheera - secrets of history, mysteries of the universe. Mysteries of great empires and ancient civilizations, the fate of disappeared treasures and biographies of people who changed the world, the secrets of special services. The history of wars, the mysteries of battles and battles, reconnaissance operations of the past and present. World traditions, modern life in Russia, the mysteries of the USSR, the main directions of culture and other related topics - all that official history is silent about.
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One day in 1722, Peter I personally cut symbolic wings from the white dress of his daughter Elizabeth. Sovereign Pyotr Alekseevich learned about this ritual in Europe and hurried to conduct it in his palace, especially since his child "passed" for twelve years. After the wings fell to the floor, Elizabeth began to be considered a bride. True, when the conversation turned to marriage in the family, Lizanka always began to cry and beg her parents to leave her at home.
Lenin argued that the NEP would lead the country out of the crisis, and Soviet power would only grow stronger, since all the levers of control would remain in the hands of the state. And the economy really took off, but the proletarian leader was slightly mistaken about the “leverage”.
Even in the harsh times of the Middle Ages, they tried not to execute sailors: it was too long and difficult to teach a good seaman. An experienced sailor was worth its weight in gold, which, however, did not prevent the ship's executioners (professors, executors - this position was called differently in the navies of different countries) in the era of sailboats to tear their servants like Sidorov's goats. But the death penalty for sailors was still quite rare. To do this, it was necessary to commit a truly terrible crime.
“Hearts made of strong damask steel” - this is how we usually talk about people, emphasizing their resilience. But do you know what bulat is? Do you remember that this word is inextricably linked with the history of Russia?
In the summer of 1941, Moscow was under martial law. The increasing frequency of German bomber raids forced the Soviet government to evacuate the most valuable archives, museum exhibits and cultural items from the capital. The mummy of V.I. Lenin.
In the heroic and tragic 30s of the 20th century, Russian women more than once demonstrated to the world their unbending strength of mind and their achievements in professions previously unthinkable for women. In October 1938, TASS announced a new aviation world record for flight range. The heavy twin-engine aircraft "Rodina", controlled by a female crew consisting of: the first pilot - Valentina Grizodubova, the co-pilot - Polina Osipenko, the navigator - Marina Raskova, flew on the route Moscow - the Far East.
Almost 30 years have passed since the collapse of the Soviet Union, but the question "Who is to blame for the death of the red empire?" is still relevant. Some believe that communism was in itself an unviable utopia, others point to the "subversive activities of capitalist intelligence." However, very little attention is given to how another giant of Western civilization, the Roman Catholic Church, contributed to the fall of communist regimes almost all over the world.
Tanzania appeared on the map in 1964 as a result of the unification of two countries - Tanganyika and Zanzibar. Before that, the real laws of the jungle reigned here - it was a colony that supplied coffee, tobacco and slaves. And only in the middle of the 20th century the country needed new people. And there were such - the son of the tribal leader Julius Nyerere was in the right place at the right time.
For many centuries, millions of human eyes with the onset of night turn their gaze upwards - towards the mysterious lights in the sky - the stars of our Universe. Ancient people saw various figures of animals and people in clusters of stars, and each of them created their own history. Later, such clusters began to be called constellations. To date, astronomers identify 88 constellations that divide the starry sky into certain areas, by which you can navigate and determine the location of the stars.
Do you know the biggest star in the entire universe?
The star VY Canis Majoris, located in the constellation Canis Major, is the largest representative of the stellar world. It is currently the largest star in the universe. The star is located 5 thousand light years from the solar system. The diameter of the star is 2.9 billion km.
In our Universe, the most numerous objects accessible to the human eye are precisely the stars. They are the source of light and energy for the entire solar system. They also create the heavy elements necessary for the origin of life. And without the stars of the Universe there would be no life, because the Sun gives its energy to almost all living beings on Earth. It warms the surface of our planet, thus creating a warm, full of life oasis among the permafrost of space. The degree of brightness of a star in the universe is determined by its size.
But not all stars in the universe are so huge. There are also so-called dwarf stars.
Comparative sizes of stars
Astronomers evaluate the magnitude of stars on a scale according to which the brighter the star, the lower its number. Each subsequent number corresponds to a star ten times less bright than the previous one. The brightest star in the night sky in the universe is Sirius. Its apparent magnitude is -1.46, which means it is 15 times brighter than a zero-magnitude star.
Stars with a magnitude of 8 or more cannot be seen with the naked eye. Stars are also divided by color into spectral classes that indicate their temperature. There are the following classes of stars in the Universe: O, B, A, F, G, K, and M. Class O corresponds to the hottest stars in the Universe - blue. The coldest stars belong to the class M, their color is red.
Spectral classes of the stars of the Universe
Class O - 30,000-60,000K blue
Class B - 10 000-30 000K white-blue
Class A - 7500-10 000K white
Class F - 6000-7500K yellow-white
Class G - 5000-6000K yellow
Class K - 3500-5000K orange
Class M - 2000-3500K red
Contrary to popular belief, it is worth noting that the stars of the universe do not actually twinkle. This is just an optical illusion - the result of atmospheric interference. A similar effect can be observed on a hot summer day, looking at hot asphalt or concrete. The hot air rises, and it seems as if you are looking through trembling glass. The same process causes the illusion of stellar twinkling. The closer a star is to Earth, the more it will "flicker" because its light travels through the denser layers of the atmosphere.
Nuclear Center of the stars of the Universe
A star in the universe is a giant nuclear focus. The nuclear reaction inside it converts hydrogen into helium through the process of fusion, so the star acquires its energy. Hydrogen atomic nuclei with one proton combine to form helium atoms with two protons. The nucleus of an ordinary hydrogen atom has only one proton. The two isotopes of hydrogen also contain one proton, but also have neutrons. Deuterium has one neutron, while Tritium has two. Deep inside a star, a deuterium atom combines with a tritium atom to form a helium atom and a free neutron. As a result of this long process, a huge amount of energy is released.
For main sequence stars, the main source of energy is nuclear reactions involving hydrogen: the proton-proton cycle, characteristic of stars with a mass near the solar one, and the CNO cycle, which occurs only in massive stars and only in the presence of carbon in their composition. In the later stages of a star's life, nuclear reactions can also take place with heavier elements, up to iron.
When a star's hydrogen supply is depleted, it begins to convert helium into oxygen and carbon. If the star is massive enough, the transformation process will continue until carbon and oxygen form neon, sodium, magnesium, sulfur, and silicon. As a result, these elements are converted into calcium, iron, nickel, chromium and copper until the core is completely metal. As soon as this happens, the nuclear reaction will stop, since the melting point of iron is too high. The internal gravitational pressure becomes higher than the external pressure of the nuclear reaction and, eventually, the star collapses. Further development of events depends on the initial mass of the star.
Types of stars in the universe
The main sequence is the period of existence of the stars of the Universe, during which a nuclear reaction takes place inside it, which is the longest segment of the life of a star. Our Sun is currently in this period. At this time, the star undergoes minor fluctuations in brightness and temperature. The duration of this period depends on the mass of the star. In large massive stars it is shorter, while in small ones it is longer. Very large stars have enough internal fuel for several hundred thousand years, while small stars like the Sun will shine for billions of years. The largest stars turn into blue giants during the main sequence.
red giant
white dwarf
brown dwarf
cepheid
double stars
Many stars in the universe are part of large star systems. Binary stars are a system of two stars gravitationally bound together. They revolve in closed orbits around a single center of mass. It has been proven that half of all the stars in our galaxy have a pair. Visually, paired stars look like two separate stars. They can be determined by the shift of the spectrum lines (Doppler effect). In eclipsing binaries, stars periodically outshine each other because their orbits are located at a small angle to the line of sight.
The life cycle of the stars of the universe
A star in the universe begins its life as a cloud of dust and gas called a nebula. The gravity of a nearby star or the blast wave of a supernova can cause the nebula to collapse. The elements of the gas cloud coalesce into a dense region called a protostar. As a result of the subsequent compression, the protostar heats up. As a result, it reaches a critical mass, and the nuclear process begins; gradually the star goes through all the phases of its existence. The first (nuclear) stage of a star's life is the longest and most stable. The lifespan of a star depends on its size. Large stars consume their life fuel faster. Their life cycle can last no more than a few hundred thousand years. But small stars live for many billions of years, as they spend their energy more slowly.
Star evolution
But be that as it may, sooner or later, stellar fuel runs out, and then a small star turns into a red giant, and a large star into a red supergiant. This phase will last until the fuel is completely used up. At this critical moment, the internal pressure of the nuclear reaction will weaken and no longer be able to balance the force of gravity, and, as a result, the star will collapse. Then the small stars of the Universe, as a rule, reincarnate into a planetary nebula with a bright shining core, called a white dwarf. Over time, it cools down, turning into a dark clot of matter - a black dwarf.
For big stars, things happen a little differently. During the collapse, they release an incredible amount of energy, and a powerful explosion gives birth to a supernova. If its magnitude is 1.4 the magnitude of the Sun, then, unfortunately, the core will not be able to maintain its existence and, after the next collapse, the supernova will become a neutron star. The internal matter of the star will shrink to such an extent that the atoms form a dense shell consisting of neutrons. If the stellar magnitude is three times greater than the solar value, then the collapse will simply destroy it, wipe it off the face of the Universe. All that remains of it is a site of strong gravity, nicknamed a black hole.
The nebula left behind by the star of the universe can expand over millions of years. In the end, it will be affected by the gravity of a nearby or the blast wave of a supernova and everything will repeat itself again. This process will take place throughout the universe - an endless cycle of life, death and rebirth. The result of this stellar evolution is the formation of heavy elements necessary for life. Our solar system came from the second or third generation of the nebula, and because of this, there are heavy elements on Earth and other planets. And this means that in each of us there are particles of stars. All the atoms of our body were born in the atomic hearth or as a result of the destructive explosion of a supernova.
List of brightest stars visible from Earth
Sirius
The star Sirius or Alpha Canis Major is the brightest star in the constellation Canis Major. With an apparent magnitude of -1.46, Sirius is the brightest star in the sky (other than the Sun). Its absolute magnitude is 1.45, and it is located at a distance of 8.6 light years.
Sirius has a spectral type of A1Vm, a surface temperature of 9940° Kelvin, and a luminosity 25 times that of the Sun. The mass of Sirius is 2.02 solar masses, the diameter is 1.7 times greater than that of the Sun.
The image above shows an uncompressed photograph of the star Sirius (North up) taken with the Takahashi E-180 astrograph.
Sirius is actually a binary star system consisting of a main sequence star designated Sirius A (spectral type A1Vm) and a faint white dwarf (spectral type DA2) designated Sirius B. The distance between Sirius A and its companion ranges between 8.1 and 31.5 astronomical units. The star Sirius is so bright because of its high intrinsic luminosity and proximity to Earth. Located 8.6 light years (2.6 parsecs) away, the Sirius system is one of Earth's closest neighbors. For the Northern Hemisphere, it is observed between 30 and 73 degrees of latitude. Sirius is the closest star to us that can be seen with the naked eye. Although Sirius is 25 times brighter than the Sun, it has a much lower luminosity than other bright stars such as Canopus, Deneb and Rigel.
The Sirius system is about 200-300 million years old. Initially, the system consisted of two bright bluish stars. The more massive Sirius B, consuming its resources, became a red giant, after which it ejected its outer layers and became a white dwarf about 120 million years ago. Sirius is colloquially known as the "Dog Star", reflecting his belonging to the constellation Canis Major. The sunrise of Sirius marked the flood of the Nile in ancient Egypt. The name Sirius comes from the ancient Greek "luminous" or "hot".
canopus
The star Canopus or Alpha Carina is the brightest star in the constellation Carina. With an apparent magnitude of -0.72, Canopus is the second brightest star in the sky. Its absolute magnitude is -5.53, and it is 310 light years away from us.
Canopus has a spectral class of A9II, a surface temperature of 7350° Kelvin, and a luminosity 13,600 times that of the Sun. The star Canopus has a mass of 8.5 solar masses and a diameter 65 times that of the Sun.
The image above shows an uncompressed photograph of the star Canopus (North up) taken with the Takahashi E-180 astrograph.
Canopus is a supergiant of spectral class F and is white when viewed with the naked eye. With a luminosity 13,600 times that of the Sun, Canopus is, in fact, the brightest star, up to 700 light-years from the solar system. If Canopus were located at a distance of 1 astronomical unit (the distance from the Earth to the Sun), then it would have an apparent magnitude of -37 (for the Sun - 26.72
The diameter of the star Canopus is 0.6 AU, or 65 times that of the Sun. If Canopus were located at the center of the solar system, then its outer edges would extend three-quarters of the way to Mercury. The Earth had to be removed to a distance of three times the orbit of Pluto in order for Canopus to look in the sky just like our Sun.
Canopus is a strong source of X-rays, which are probably produced by its corona, heated to 15 million degrees Kelvin. It is a member of the Scorpio-Centaurus group of stars that share a common origin.
Arcturus
The star Arcturus or Alpha Bootes is the brightest star in the constellation Bootes. With an apparent magnitude of -0.04, Arcturus is the fourth brightest star in the sky. Its absolute value is -0.3 and it is 34 light years away from us.
The star Arcturus has a spectral type of K1.5IIIp, a surface temperature of 4300° Kelvin, and a luminosity 210 times that of the Sun. Its mass is 1.1 solar masses, and its diameter is 26 solar diameters.
The image above shows an uncompressed photograph of the star Arcturus (North up) taken with the Takahashi E-180 astrograph.
Arcturus is visible in both hemispheres in the sky, as it is located less than 20 degrees north of the celestial equator. The star reaches its zenith at midnight on April 30th. There is an easy way to find the star Arcturus. It is only necessary to follow the handle of the Big Dipper bucket. Continuing in this direction, one can find Spica. Arcturus is the star of the local interstellar cloud.
Arcturus is an orange giant of the K1.5IIIp spectral class. The "P" stands for "exceptional emission", indicating that the spectrum of light coming from the star is unusual and full of emission lines. This phenomenon is not very common among red giants, but is typical for the star Arcturus. The star is at least 110 times more visually luminous than the Sun, and that doesn't take into account the fact that the star emits a large amount of light in the infrared. The total (bolometric) power is 180 times greater than that of the Sun.
Arcturus is notable for its high speed of its own motion. It is greater than the speed of any first magnitude star in the vicinity, except for Alpha Centauri. The star Arcturus is moving fast (122 km/s) compared to the Solar System and is currently at almost its closest point to the Sun. It will take another 4,000 years for the star to get a few hundredths of a light year closer to Earth than it is today. Arcturus is considered an old star and moves with a group of 52 other similar stars. This movement is known as the Arcturus current. Its mass is difficult to determine, but presumably it is 1.1 solar masses.
Vega
The star Vega or Alpha Lyrae is the brightest star in the constellation Lyrae. With an apparent magnitude of 0.03, Vega is the fifth brightest star in the sky. Its absolute value is 0.6, the distance from the Earth is 25 light years.
Vega has a spectral type of A0Va, a surface temperature of 9600° Kelvin, and its luminosity is 37 times that of the Sun. The mass of the star is 2.1 solar masses, the diameter is 2.3 times that of the Sun.
The image above shows an uncompressed photograph of the star Vega (North up) taken with the Takahashi E-180 astrograph.
Vega is a relatively nearby star located 25 light years from Earth. Together with Arcturus and Sirius, it is one of the brightest stars in the vicinity of the Sun. Vega is one of the vertices of the Summer Triangle along with Deneb and Altair. Since it is located high in the sky, it is clearly visible throughout the summer months.
Vega has a spectral type of A0Va, making it a white main sequence star with a bluish tint. At present, its age is estimated at 455 million years. Vega is only a tenth of the age of the Sun, but given that it is 2.1 times as massive as it is, its estimated lifespan would also be only a tenth of the Sun. Both stars have now reached the midpoint of life. Vega has an unusually low abundance of elements with an atomic number greater than that of helium.
It is also assumed that Vega is a variable star that differs slightly in magnitude on a periodic basis. It rotates quite quickly, while the speed at the equator reaches 274 km / s. This causes the equator to bulge outward under the influence of centrifugal force and, as a result, there is a change in temperature throughout the star's photosphere, reaching a maximum at the poles. From Earth, Vega is observed from one of these poles.
Based on the observed excess of infrared radiation, Vega is likely to have a circumstellar dusty disk. This dust, which is the result of collisions between objects, forms an orbital disk of debris, similar to the Kuiper belt in the solar system. Stars that have an excess of infrared radiation are called Vega-type stars. Vega's disc instability also suggests the presence of at least one planet the size of Jupiter.
Vega was the star of the north pole until 12000 BC. and will be so after 13700 AD. Vega was the first star (after the Sun) to be photographed and the first to have its spectrum recorded. She was also one of the first stars whose distance was estimated by parallax measurements.
Chapel
Star Capella or Alpha Aurigae is the brightest star in the constellation Auriga. With an apparent magnitude of 0.08, Capella is the sixth brightest star in the sky. Its absolute value is -0.5, and the distance from the Earth is 41 light years.
The chapel has a spectral type of G6III + G2III, a surface temperature of 4940° Kelvin, and its luminosity is 79 times greater than that of the Sun. The mass of the star is 2.69 the mass of the Sun, and the diameter is 12 times greater than that of the Sun.
The image above shows an uncompressed photograph of the star Capella (North up) taken with the Takahashi E-180 astrograph.
Although, to the naked eye, Capella appears to be a single star, it is actually formed by two binary pairs. The first pair consists of two bright giant G-type stars with a radius 10 times greater than that of the Sun, and are in close relationship. These stars are thought to be on their way to becoming red giants.
The first star has a surface temperature of about 4900 K, a radius 12 times that of the Sun, a mass of 2.7 solar masses, and a luminosity 79 times that of the Sun. The second star has a surface temperature of about 5700K, a radius equal to 9 solar radii, a mass of 2.6 solar masses, and a luminosity 78 times that of the Sun. Although the primary star is brighter when viewed at all wavelengths, it appears fainter when viewed in visible light, with an apparent magnitude of approximately 0.91, compared to an apparent apparent magnitude of 0.76.
The second binary pair consists of two faint, small, and relatively cool red dwarfs. The pair is located at a distance of 10,000 astronomical units (100 million km) and has an orbital period of about 104 days. Apparently, stars throughout their lives were main-sequence stars of the spectral A-class, but at the moment they are expanding, cooling and becoming red giants. This process will take them another few million years.
Rigel
The star Rigel or Beta Orionis is the brightest star in the constellation Orion. With an apparent magnitude of 0.12, Rigel is the seventh brightest star in the sky. Its absolute magnitude is -7 and it is located at a distance of ~870 light-years from us.
Rigel has a spectral class of B8Iae, a surface temperature of 11,000 Kelvin, and its luminosity is 66,000 times greater than that of the Sun. The star has a mass of 17 solar masses and a diameter 78 times that of the Sun.
The image above shows an uncompressed photograph of the star Rigel (North up) taken with the Takahashi E-180 astrograph.
Rigel is the brightest star in our local region of the Milky Way. The star is so bright that when viewed from a distance of one astronomical unit (the distance from the Earth to the Sun), it will shine as an extremely bright ball with an angular diameter of 35° and an apparent magnitude of -38. The power flow at this distance will be the same as from a welding arc from a distance of a few millimeters. Any object so close will be vaporized by the strong stellar wind.
Rigel is currently passing through the region of the nebula. Consequently, the star illuminates several dust clouds located nearby. The most prominent of these is IC 2118 (the Witch's Head Nebula). Rigel is also associated with the Orion Nebula (M42), which is more or less in the same visual line as the star, although it is located almost twice as far from Earth.
Rigel is a famous binary star, which was first observed by Vasily Yakovlevich Struve in 1831. Although Rigel B has a relatively faint magnitude, its proximity to Rigel A, which is 500 times brighter, makes it one of the targets of amateur astronomers. According to calculations, Rigel B is removed from Rigel A at a distance of 2200 astronomical units. Due to such a colossal distance between them, there is no sign of orbital motion, although they have the same proper motion.
Rigel B itself is a spectroscopic binary consisting of two main sequence stars orbiting a common center of gravity every 9.8 days. Both stars belong to the spectral class B9V.
Rigel is a variable star, which is not common in supergiants, with a magnitude range of 0.03-0.3, changing every 22-25 days.
Procyon
The star Procyon or Alpha Canis Minor is the brightest star in the constellation Canis Minor. With an apparent magnitude of 0.38, Procyon is the eighth brightest star in the night sky. Its absolute magnitude is 2.6, and the distance to Earth is 11.4 light years.
Procyon has a spectral type of F5IV-V, a surface temperature of 6650° Kelvin, and a luminosity 6.9 times greater than that of the Sun. The mass of the star is 1.4 times the mass of the Sun, and the diameter is 2 times.
The image above shows an uncompressed photograph of the star Procyon (North up) taken with the Takahashi E-180 astrograph.
To the naked eye, Procyon looks like a single star. In fact, Procyon is a binary star system consisting of a main sequence white dwarf (spectral class F5 IV-V) called Procyon A and a faint white dwarf (spectral class DA) called Procyon B. Procyon looks so bright not because of its luminosity, but due to proximity to the Sun. The system is located at a distance of 11.46 light years (3.51 parsecs) and is one of our closest neighbors.
The surface temperature of Procyon A is estimated to be 6530° Kelvin, giving it a white tint. The mass of Procyon A is 1.4 solar masses, the radius is equal to two solar radii, and its luminosity is 6.9 times greater than that of the Sun. Procyon A is fairly bright for its class, implying complete conversion of hydrogen to helium at its core. Ultimately, the star will begin to expand and increase in volume from 80 to 150 times. This should happen within 10 to 100 million years.
Like Sirius B, Procyon B is a white dwarf that was isolated as a separate entity long before it was observed. Its existence was first predicted by Friedrich Bessel in 1844. Although its orbital characteristics were calculated by Arthur Overs in 1862, Procyon B was not visually confirmed until 1896, when John Martin Scheberle observed it at the predicted coordinates with a 36-inch refractor at the Lick Observatory.
With a mass of 0.6 solar masses, Procyon B is significantly less massive than Sirius B. However, Procyon B is structurally larger than its better-known neighbor, with an estimated radius of 8600 km, compared to 5800 km for Sirius B. Surface temperature star Procyon B is 7740° Kelvin, which is also much colder than Sirius B. This indicates its lower mass and greater age. Procyon B's progenitor star had a mass of about 2.5 solar masses and came to the end of its life approximately 1.7 billion years ago. For this reason, Procyon A is thought to be 2 billion years old.
The star Procyon forms one of the three peaks of the Winter Triangle, along with Sirius and Betelgeuse.
Betelgeuse
The star Betelgeuse or Alpha Orionis is the second brightest star in the constellation Orion. With an apparent magnitude of 0.5, Betelgeuse is the ninth brightest star in the night sky. Its absolute magnitude is -5.14, and the distance to Earth is 530 light years.
Betelgeuse has a spectral type M2Iab, a surface temperature of 3500° Kelvin, and a luminosity 140,000 times that of the Sun. The star has a mass equal to 18 solar masses and a diameter equal to 1180 solar diameters.
The image above shows an uncompressed photograph of the star Betelgeuse (North up) taken with the Takahashi E-180 astrograph.
The red supergiant Betelgeuse is one of the largest and brightest stars known. If it were located in the center of our solar system, its surface would swallow up the entire inner part of the solar system (Mercury, Venus, Earth and Mars), go beyond the asteroid belt and possibly reach Jupiter. However, due to the fact that the distance between the star and the Earth has changed over the past century in the range from 180 to 1300 light years, it is rather difficult to calculate its diameter and luminosity. Betelgeuse is currently thought to be located 640 light-years from Earth, giving it an average absolute magnitude of around -6.05.
In 1920 Alpha Orionis became the first star (after the Sun) to have its angular diameter measured. Since then, researchers have used a number of telescopes to measure this stellar giant, each with different technical parameters, often with conflicting results. The current visible range of the star's diameter ranges from 0.043 to 0.056 seconds. This is a real moving target, as the star Betelgeuse periodically changes shape. In addition, Betelgeuse has a complex, asymmetric shell caused by the colossal loss of mass due to huge jets of gas escaping from the surface. There is even evidence that Betelgeuse has a stellar companion orbiting its gaseous envelope, contributing to the star's eccentric behavior.
Betelgeuse is believed to be only 10 million years old, but it evolved rapidly due to its high mass. The star appears to be an escapee from the Orion OB1 star cluster, which includes O and B type stars in Orion's belt (Alnitak, Alnilam, and Mintaka). Betelgeuse is currently in a late evolutionary stage and is expected to explode as a Type II supernova in the next millions of years.
With a distinct reddish tint, it is a semi-regular variable star whose apparent magnitude varies between 0.2 and 1.2. The star is the upper right corner of the Winter Triangle, along with Sirius and Procyon.
Betelgeuse is easy to spot in the night sky, as it appears in close proximity to Orion's famous belt. In the northern hemisphere, it can be seen growing in the east just after sunset in January. By mid-March, the star appears in the south in the evening sky and is visible to virtually every inhabited region of the globe. In major cities in the southern hemisphere (such as Sydney, Buenos Aires and Cape Town), the star rises almost 49° above the horizon.
Altair
The star Altair or Alpha Aquila is the brightest star in the constellation Aquila. With an apparent magnitude of 0.77, Altair is the 12th brightest star in the night sky. Its absolute magnitude is 2.3, and the distance to Earth is 18 light years.
Altair has a spectral type of A7Vn, a surface temperature of 7500° Kelvin, and a luminosity 10.6 times that of the Sun. Its mass is 1.79 solar masses, and its diameter is 1.9 times greater than that of the Sun.
The image above shows an uncompressed photograph of the star Altair (North up) taken with the Takahashi E-180 astrograph.
Located 18 light-years (5.13 parsecs) away, Altair is one of the closest stars visible to the naked eye. Along with Beta Aquila and Tarazed, the star forms a well-known line of stars sometimes called the Aquila family. Altair forms one of the vertices of the Summer Triangle along with Deneb and Vega.
Altair is an A-type main sequence star. It has an extremely high rotation speed, which reaches 210 kilometers per second at the equator. Thus, one period is about 9 hours. By comparison, the Sun takes just over 25 days to complete one full rotation at the equator. This rapid rotation causes the Altair to be slightly flattened. Its equatorial diameter is 20 percent larger than the polar one.
Aldebaran
The star Aldebaran or Alpha Taurus is the brightest star in the constellation Taurus. With an apparent magnitude of 0.85, Aldebaran is the 14th brightest star in the night sky. Its absolute magnitude is -0.3, and the distance to Earth is 65 light years.
Aldebaran has a spectral type of K5III, a surface temperature of 4010° Kelvin, and a luminosity 425 times that of the Sun. The star Aldebaran has a mass of 1.7 solar masses and a diameter that is 44.2 times that of the sun.
The image above shows an uncompressed photograph of the star Aldebaran (North up) taken with the Takahashi E-180 astrograph.
Aldebaran is an orange giant that has moved from the main line of the Hertzsprung-Russell sequence. It has exhausted the hydrogen fuel in its core and the hydrogen fusion process has ceased. Although not yet high enough to fuse helium, the temperature of the star's core increased significantly due to gravitational pressure, and the star expanded to 44.2 solar diameters, reaching a value of 61 million kilometers. The Hipparcos satellite measured the distance to the star, which is 65 light years (20.0 parsecs). Aldebaran is a slightly variable LB star. Its fluctuations in apparent magnitude are about 0.2.
Aldebaran is one of the simplest stars to be found in the night sky, partly because of its brightness and partly because of its spatial location in relation to one of the most prominent asterisms in the sky. If you follow the three stars in Orion's belt from left to right (northern hemisphere) or right to left (south), the first bright star you find as you continue along this line is Aldebaran.
Aldebaran is brightest among members of the Hyades group of open star clusters, which make up the "bull's head" in the constellation Taurus. However, Aldebaran just happened to be in line of sight between Earth and the Hyades. The star cluster is actually located twice as far away, at a distance of 150 light years.
The name Aldebaran comes from Arabic and literally translates as "follower", apparently due to the fact that this bright star seems to follow the Pleiades or the Seven Sisters star cluster in the night sky.
Antares
The star Antares or Alpha Scorpii is the brightest star in the constellation Scorpio. With an apparent star of 0.96, Antares is the 16th brightest star in the sky. Its absolute magnitude is -5.28 and its distance from Earth is 604 light years.
Antares has a spectral type of M1.5Iab, a surface temperature of 3500° Kelvin, and a luminosity 65,000 times that of the Sun. The mass of the star is 15.5 solar masses, and its diameter is 800 times greater than that of the Sun.
The image above shows an uncompressed photograph of the star Antares (North up) taken with the Takahashi E-180 astrograph.
Antares is a supergiant. If it is placed in the center of the solar system, then its outer surface will be between the orbits of Mars and Jupiter. Based on parallax measurements, Antares is 550 light-years (170 parsecs) from Earth. Antares has a visual luminosity 10,000 times that of the Sun, but since the star emits a significant amount of energy in the infrared, its bolometric luminosity is 65,000 times greater than that of the Sun. Antares is also an irregular variable star (type LC) whose apparent magnitude ranges from 0.88 to 1.16.
Antares is in opposition to the Sun around May 31 of each year. At this time, the star is visible throughout the night. For about two to three weeks before and after November 30, Antares is not visible in the night sky, as it is lost in the glare of the Sun. Along with Aldebaran, Spica and Regulus, it is one of the four brightest stars located near the ecliptic.
Antares has a secondary companion star, Antares B, whose angular separation changed from 3.3 arc seconds in 1854 to 2.86 arc seconds in 1990. The star is generally hard to see due to the glare from Antares A.
spica
The star Spica or Alpha Virgo is the brightest star in the constellation Virgo. With an apparent magnitude of 0.98, Spica is the 15th brightest star in the night sky. Its absolute magnitude is -3.2, and the distance to Earth is 262 light years.
Spica has a spectral type of B1V, a surface temperature of 22,400° Kelvin, and a luminosity 12,100 times that of the Sun. Its mass reaches 10.3 solar masses, and its diameter is 7.4 solar diameters.
The image above shows an uncompressed photograph of the star Spica (North up) taken with the Takahashi E-180 astrograph.
Spica is a close binary star whose components complete one revolution around a common center of mass every four days. They are located close enough to each other that they cannot be seen in a telescope as two separate stars. Changes in the orbital motion of this pair result in a Doppler shift in the absorption lines of their respective spectra, making them a spectral binary pair. The orbital parameters for this system were first derived using spectroscopic measurements.
The main star has a spectral type B1 III-IV. The luminosity class does not match the star's spectrum, which lies between a subgiant and a giant star, and it is no longer a B-type main sequence star. It is a massive star with 10 times the mass of the Sun and seven times the radius. The total luminosity of this star is 12,100 times that of the Sun and eight times that of its companion. The primary star of this pair is one of the closest stars to the Sun that has enough mass to end its life in a Type II supernova explosion.
The host star is classified as a Beta Cephei type variable star, which changes in brightness by a value of 0.1738 every day. The spectrum shows the radial velocity variation with the same period, indicating that the surface of the star is regularly pulsating. This star is spinning fast. The rotation speed along the equator is 199 km/s.
The secondary star of this system is one of the few stars in which the Struve-Sahade effect is observed. This is an anomalous change in the strength of the spectral lines during an orbit, where the lines become weaker as the star moves away from the observer. This star is smaller than the main one. Its mass is seven times that of the Sun, and the radius of the star is 3.6 times the radius of the Sun. The star has a spectral type of B2 V, making it a main sequence star.
Spica is an ellipsoidal variable where stars are distorted by the gravitational force. This effect causes a change in the apparent stellar magnitude of the star system by a value equal to 0.03 per time interval, which corresponds to the orbital period. This small decrease in magnitude is barely noticeable visually. The rotation rates of both stars are faster than their orbital period. This lack of synchronization and the high ellipticity of their orbit may indicate that this is a young star system. Over time, the mutual tidal interaction of the pair can lead to rotational synchronization and orbit cyclization.
Pollux
The star Pollux or Beta Gemini is the brightest star in the constellation Gemini. With an apparent magnitude of 1.14, Pollux is the 17th brightest star in the sky. Its absolute magnitude is 0.7, and the distance to Earth is 40 light years.
Pollux has a spectral type of K0IIIb, a surface temperature of 4865° Kelvin, and a luminosity 32 times that of the Sun. Its mass is 1.86 solar masses, and its diameter is 8 times greater than that of the Sun.
The image above shows an uncompressed photograph of the star Pollux (North up) taken with the Takahashi E-180 astrograph.
The twin stars Castor and Pollux are best seen during northern spring evenings. Unlike real-life twins, Castor and Pollux have little in common. Castor is a white quadruple star composed of fairly close white components (spectral class A), while Pollux is an orange cool giant (spectral class K0IIIb).
Close pairing with Castor gives Pollux a brighter color. A star located 34 light-years away has a total luminosity 46 times that of the Sun. With its cold temperature (4770° Kelvin) and a diameter 10 times that of the Sun, Pollux is smaller than most of its cool giant cousins and only a quarter of the diameter of Aldebaran. In its deep core, the process of hydrogen fusion into helium takes place, which is typical for most red giants. The star emits X-rays and appears to have a magnetized corona.
In 2006, an exoplanet was discovered orbiting Pollux, making it the brightest star in the sky with a known exoplanet. With a mass at least 2.9 times that of Jupiter, the planet is in a circular orbit at a distance of 1.69 astronomical units, with a rotation period of 590 days (1.6 years).
Fomalhaut
The star Fomalhaut, or alpha Southern Fish, is the brightest star in the constellation Southern Fish. With an apparent magnitude of 1.16, Fomalhaut is the 18th brightest star in the sky. Its absolute magnitude is 2.0, and it is located at a distance of 22 light years.
Fomalhaut has a spectral type of A3Va, a surface temperature of 8750° Kelvin, and a luminosity 17.9 times that of the Sun.
The image above shows an uncompressed photograph of the star Fomalhaut (North up) taken with the Takahashi E-180 astrograph.
Fomalhaut is a relatively young star, about 300 million years old, with a potential lifespan of up to a billion years. The star has a metal deficiency compared to the Sun, which means that it is made up of a smaller percentage of elements other than hydrogen and helium. The metallicity of a star is determined by measuring the abundance of iron in the photosphere relative to hydrogen. In 1997, spectroscopic studies showed a value equal to 93% of the volume of iron in the Sun, but more recent studies have shown that the value may actually be half that.
Fomalhaut is one of 16 stars belonging to the Castor Moving Group of Stars. This is an association of stars that shares the general movement of stars in space and therefore can be physically connected. The other members of this group are Castor and Vega. This moving group is estimated by scientists to be about 200 million years old. The neighboring star TW Southern Pisces, which is also a member of this group, may form a physical pair with Fomalhaut.
Fomalhaut is surrounded by a toroidal debris disk with a very sharp inner edge at a radial distance of 133 AU. The dust is distributed in a belt about 25 AU wide and is sometimes referred to as the "Fomalhaut Kuiper Belt". The dusty disk of Fomalhaut is believed to be protoplanetary and emit infrared radiation. Fomalhaut's rotation measurements indicate that the disk is in the star's equatorial plane, as suggested by the theory of star and planet formation.
Fomalhaut is of particular importance in exosolar research as it is the center of the first star system with an exoplanet (Fomalhaut b) seen at visible wavelengths. The mass of the planet is approximately no more than three times the mass of Jupiter and no less than the mass of Neptune.
Deneb
The star Deneb or Alpha Cygnus is the brightest star in the constellation Cygnus. With an apparent magnitude of 1.25, Deneb is the 19th brightest star in the sky. Its absolute magnitude is -7.2, and the distance to Earth is 1550 light years.
Deneb has a spectral type of A2Ia, a surface temperature of 8525° Kelvin, and a luminosity 54,000 times that of the Sun. Its mass is 20 solar masses, and its diameter is 110 solar diameters.
The image above shows an uncompressed photograph of the star Deneb (North up) taken with the Takahashi E-180 astrograph.
Deneb together with Altair and Vega form the tops of the Summer Triangle. With an absolute magnitude of 7.2, Deneb is one of the brightest stars we know. Its luminosity is estimated to be 60,000 times that of the Sun. Its exact distance to Earth is unknown, making determinations of many of Deneb's other properties also inaccurate. However, the veil of uncertainty over this star was lifted by research in 2007. According to the results, the most likely distance at which the star is located is about 1550 light years. The calculation error allows a distance from 1340 to 1840 light years. Deneb is the most distant known star of the first magnitude.
Based on its temperature and luminosity, as well as direct measurements of its tiny angular diameter (only 0.002 arcseconds), Deneb appears to have a diameter that is 110 times that of the Sun. If placed in the center of our solar system, Deneb would take up half the path of the Earth's orbit. Alpha Cygnus is one of the largest white stars we know.
The supergiant's blue-white color, high mass and temperature means the star will have a very short lifespan and will likely go supernova within a few million years. In its core, the process of hydrogen fusion is already stopping. At present, it is likely that Deneb is expanding into a red supergiant like Mu Cephei. While it will, the star will pass through spectral types F, G, K, and M.
Deneb's solar wind causes it to lose mass at a rate of 0.8 million solar masses per year, 100,000 times the flow from the Sun. It is the prototype of a class of variable stars known as Alpha Cygnus variables. Its surface is subject to non-radial vibrations that cause changes in its brightness and spectral type.
Regulus
The star Regulus or Alpha Leo is the brightest star in the constellation Leo. With an apparent magnitude of 1.35, Regulus is the 21st brightest star in the sky. Its absolute value is -0.3, and the distance to the Earth is 69 light years.
Regulus has a spectral class of B7Vn, a surface temperature of 10300° Kelvin and a luminosity 150 times that of the Sun. The mass of the star is 3.5 solar masses, and the diameter is 3.2 solar diameters.
The image above shows an uncompressed photograph of the star Regulus (North up) taken with the Takahashi E-180 astrograph.
Regulus is a multiple star system consisting of four stars. Regulus A is a binary star system consisting of a white-bluish main sequence star (spectral class B7V), which is supposedly orbiting a white dwarf with a mass of 0.3 solar masses. It takes these two stars about 40 days to complete one complete orbit around their common center of mass.
The main star Regulus A is a young star with a mass of about 3.5 masses of the Sun, whose age is several hundred million years. The star is spinning pretty fast. Its period is only 15.9 hours, which leads to a distortion of the shape of the star and to the so-called gravitational eclipse: the photosphere at the poles of this star is much hotter and five times brighter per unit surface area than at the equatorial region. If it rotated 16% faster, then the star's gravity would be weaker than the centrifugal force and the star would tear itself apart.
Given the highly distorted shape of the main star, the relative orbital motion of a binary pair can be strikingly different from pure two Kepler bodies due to constant perturbations affecting their orbital period. In other words, Kepler's third law, which is defined for two point masses, does not apply to this binary pair due to the too distorted shape of the main star.
At a distance of about 4200 astronomical units from Regulus A, there is a binary star system that shares a common proper rotation. Designated as Regulus B (spectral class K2V) and Regulus C (spectral class M4V), the pair have an orbital period of 2000 years and are separated by about 100 astronomical units.
The light emanating from this pair of stars dominates the binary pair Regulus A. Regulus B, when viewed separately, is a binocular object with an apparent star of magnitude 8.1, and its stellar companion Regulus is 13.5. Regulus A is a spectroscopic binary star: the secondary star of this pair has not yet been directly observed, since it is much fainter than the main one. Pair B and C are located at an angular distance of 177 arc seconds from Regulus A, making it invisible to amateur telescopes.
Of the brightest stars in the sky, Regulus is closest to the plane of the ecliptic and is regularly obscured by the Moon. Mercury and Venus occultations are also possible, but rare, as is asteroid occultation. The last planetary eclipse (planet Venus) of the star Regulus occurred on July 7, 1959. The next one will happen on October 1, 2044 and also by Venus. Other planets will not obscure Regulus for the next few millennia due to their positions.
Adara
The Star of Adara, or Epsilon Canis Major, is the second brightest star in the constellation Canis Major. With an apparent magnitude of 1.5, Adara is the 22nd brightest star in the sky. Its absolute value is -4.8, and the distance to the Earth is approximately 400 light years.
Adara has a spectral type B2II, a surface temperature of 24,750° Kelvin, and a luminosity 20,000 times that of the Sun. The star has a mass of 10 solar masses.
The image above shows an uncompressed photograph of the star Adara (North up) taken with the Takahashi E-180 astrograph.
Adara is a binary star 430 light-years away from Earth. The main star has a bluish-white color (spectral class B2) with a high surface temperature (25,000° K). It emits a total radiation that is 20,000 times greater than that of the Sun. If this star were at the same distance as Sirius, it would outshine all other stars in the sky and be 15 times brighter than the planet Venus. This star is also one of the most powerful ultraviolet sources in the sky. This is a strong source of photons capable of ionizing hydrogen atoms in the interstellar gas near the Sun, and this is very important in determining the state of ionization of the interstellar cloud.
The companion star has an apparent magnitude of 7.5 and is located 7.5 arc seconds from the main star. However, this star can only be seen in large telescopes, as the main star is about 250 times brighter than its companion.
A few million years ago, Adara was much closer to the Sun than it is at present, causing it to be much brighter in the night sky. About 4,700,000 years ago, Adara was located 34 light-years from the Sun and was a very bright star with an apparent magnitude of -3.99. No other star has reached this brightness since then, and no other star will achieve this brightness in the next five million years.
Castor
The star Castor or Alpha Gemini is the second brightest star in the constellation Gemini. With an apparent magnitude of 1.57, Castor is the 23rd brightest star in the sky. Its absolute magnitude is 0.5, and its distance from Earth is 49 light years.
Castor has a spectral type of A1V + A2V, a surface temperature of 10,300° Kelvin, and a luminosity 30 times that of the Sun. The mass of the star is 2.2 solar masses, and the diameter is 2.3 times greater than that of the Sun.
The image above shows an uncompressed image of the star Castor (North up) taken with the Takahashi E-180 astrograph.
Visually, the double star Castor was discovered in 1678. Its apparent magnitude is 2.0 and 2.9 (the combined magnitude is 1.58). Separated hot white stars (spectral class A) are 6 arcseconds apart, and their orbital period around their common center of mass is 467 years. Each of the components of this pair is itself a spectroscopic binary, making castor a quadruple star system. Castor has a faint companion, distant from it by 72 arc seconds, but with the same parallax and proper motion. This satellite is a binary obscured star system with a period of about 1 day. This binary star system is just one of several in which both components of the pair are M-class dwarf stars. Castor can thus be considered a sixfold star system, with six individual stars gravitationally bound to each other.
Twins of the "twins" - the stars Castor and Pollux are best seen during spring evenings. Unlike real-life twins, Castor and Pollux have little in common. Castor is a white quadruple star composed of fairly close white components (spectral class A), while Pollux is an orange cool giant (spectral class K0IIIb). Close pairing with Castor gives Pollux a brighter color.
