One of the stars in the night sky is the brightest Betelgeuse. It is located in the constellation Orion. It can be seen in the night sky even without special instruments. The size of the star is amazing. It exceeds the mass of the Sun by 20 times in its mass, and by more than 1000 times in diameter. The distance to Betelgeuse is estimated at just over 600 light years (the distance traveled by light in a year at a speed of 300,000 km / h is 1 light year).
Betelgeuse (translated from Arabic as "twin's armpit") is a supermassive red giant. If you take it and put it in the place of the Sun, then it would reach the orbit of Jupiter, while covering all the planets that are inside. Our Sun will emit light 50 thousand times less when compared with Betelgeuse. By galactic standards, this star is still young - about 10 million years old. Stars belonging to red supergiants live very short lives. Considering the huge pressure inside the star created by its colossal mass, it burns its fuel very quickly, which directly affects the lifetime of the star itself.
Star life
The birth of a star is no different from the birth of other stars. In the vastness of the galaxy, a molecular cloud of a spherical shape is formed, a protostar. Then thermonuclear fusion began under the enormous pressure of the mass of the star. This process leads to the heating of the core. At this stage, hydrogen begins to turn into helium, while huge energy is released into space. Thanks to this energy, the star does not shrink.
Over time, hydrogen ends, which accordingly entails a loss of energy and the star still begins to shrink. The core begins to shrink with even greater force until the moment when helium begins to go into another state - turn into carbon. Then there is a helium flash. At this point, the star begins to release an enormous amount of energy. From an ordinary star, it turns into a red giant. At this stage of life is Betelgeuse.
New elements appear (neon, oxygen, etc.) before the formation of iron. Over time, the fuel runs out, and the core begins to shrink again. Inside the star, the iron core is compressed, which subsequently becomes neutronic. Then there is a huge explosion. This explosion is the formation of a type 2 supernova. Instead of a core, a black hole or a neutron star can form.
Is there a danger to the Earth?
There is no definite answer to the question of when Betelgeuse will explode. Some scientists believe that it will happen very soon (in the next 2 thousand years), and there are those who believe that it will happen much later. For our planet, this explosion does not carry any danger. However, if the explosion occurs in our time, then one can observe an amazingly beautiful picture in the sky. The brightness of Betelgeuse will be comparable to the Moon, both day and night. However, after a few years, the visibility will fade and then gradually disappear completely. And in its place is formed.
Light of Orion. A second sun may appear in the sky.
According to sources at the Mauna Kea observatory in Hawaii, the red giant Betelgeuse, located in the constellation of Orion, is rapidly changing its shape.
Only in the last 16 years the star has ceased to be round, it has shrunk at the poles. Such symptoms may indicate that in the very near future (we are talking about months, perhaps even weeks), the star will turn into a supernova.
Earthlings will be able to observe this event with the naked eye. A very bright star will flash in the sky. Scientists differ in their estimates of the degree of brightness, some say that it will be equal to the Moon, others promise the appearance of a second Sun.
The whole transformation will take about six weeks. In some parts of the Earth they will learn what white nights are, the rest of the unusual phenomenon will add two to three hours of daylight hours.
Then, the star will finally cool down and will be visible to earthlings in the form of a nebula.
For people, such events in space are not dangerous.
Waves of charged particles - a consequence of the explosion, of course, will reach our planet, but this will happen in a few centuries. Our distant descendants will receive a small dose of ionizing radiation.
The last time such an event was available to the eyes of earthlings was in 1054.
Betelgeuse (alpha).
largest visible star
On the right shoulder of Orion, in the crown of the Winter Hexagon, the beautiful Betelgeuse shines in the winter skies.
Constellation of Orion. Betelgeuse is a reddish-orange star in the upper left corner of the constellation.
This star is called alpha Orion for a reason, although the dazzling bluish Rigel - in the photo in the lower right corner - is brighter most of the time. Betelgeuse is in many ways a unique star that astronomers have been exploring for many years and discovering more and more interesting facts.
First, Betelgeuse is one of the largest stars in the universe. Its diameter is more than the diameter of the Sun by about a thousand times. Even the largest known star, VY Canis Major, is only twice the diameter of Betelgeuse (and therefore eight times the volume). So it is not in vain that this star bears the proud title of a red supergiant.
If it were in place of the Sun, it would almost fill the orbit of Saturn:
Only eight known stars (all red hypergiants) surpass Betelgeuse in volume, but they all look very dim in the earth's sky. The reason is simple: Betelgeuse is much closer than all of them.
Betelgeuse is 640 light-years away, which is very short on the scale of the Galaxy. Betelgeuse is the closest supergiant to us.
An interesting conclusion follows from this: Betelgeuse in the earth's sky has the largest apparent diameter of all stars (after the Sun, of course.)
It is clear that everything that is less than an arc minute in diameter is perceived by the human eye as a point. The angular diameters of absolutely all stars (except the Sun) are less than an arc minute, so they all look like dots. In fact, of course, all their angular diameters are different. The angular diameter of Betelgeuse was first determined in 1920 as 0.047 arcseconds, which was the largest angular diameter of a star then known. Since then, however, the star R Doradus, invisible in the northern hemisphere, has been discovered, the angular diameter of which turned out to be 0.057 arcseconds. But even in the southern hemisphere it is almost invisible: at maximum brightness it is hardly visible to the naked eye, and at minimum it can not be seen with every telescope. R Doradus is so cold that it emits mostly infrared radiation. But since then, the angular measurements have been refined, and for Betelgeuse, the apparent diameter is determined from 0.056 to 0.059 arcseconds, which restores to it the lost positions of the largest visible star. It's not so easy to push the queen of winter skies!
Not surprisingly, Betelgeuse was the first star for which disk photographs were taken. That is, on which the star looked not like a point, but a disk. (That the bright stars appear as disks in the above photograph is a convention of the image, which can only convey a difference in brightness by a difference in size.) The photo was taken by the Hubble Space Telescope in 1995.
Here is a historical UV image (NASA/ESA credit):
It is clear that the colors in the photograph are arbitrary: the redder, the colder. A bright spot near the center of the star is considered one of its poles, that is, the axis of rotation of Betelgeuse is directed almost towards us, but slightly to the side.
More recently, namely in July last (2009), new photographs of Betelgeuse were taken with the ground-based Very Large Telescope (VLT) in Chile. Here is one of them:
The resulting photos show that Betelgeuse has a tail. This tail stretches for six radii of Betelgeuse itself (comparable to the distance from the Sun to Neptune). What kind of tail it is, why it is there and what it means, scientists themselves do not yet know, although there are many assumptions.
Measuring Betelgeuse
It is interesting to give the main parameters of Betelgeuse. We will see that in almost all respects, Betelgeuse turns out to be one of the “winners” of the known Universe.
In diameter, as already mentioned, Betelgeuse exceeds the Sun by about a thousand times. It is very difficult to accurately determine the diameter and distance from the Sun of a single star, and no satellites have been found in Betelgeuse (although it is very possible that they are, they just cannot be seen next to such a hulk). But Betelgeuse is so huge that its diameter could be measured "directly", i.e. with the help of an interferometer - this operation could be applied to a very small number of stars, and Betelgeuse was the first.
In terms of mass, Betelgeuse exceeds the Sun by about 15 times (from 10 to 20 - to measure the mass of a single star is generally the aerobatics of astrometry, more precisely, it has not yet been possible). How can it be, a thousand times larger in diameter, which means that it is a billion times larger in volume, and only 15 times larger in mass, what is the density there? But this one. And if we take into account that the core of a star is much denser than its outer layers, then the outer layers of Betelgeuse are much rarer than anything that we can imagine, except for interstellar space, into which Betelgeuse, like almost any star, passes very gradually, i.e. it is impossible to determine exactly where the star ends and interstellar space begins. Nevertheless, fifteen solar masses is quite a lot for a star. Only 120 known stars are heavier than Betelgeuse.
How many times is Betelgeuse brighter than the Sun? One hundred thirty-five thousand times! True, this is taking into account infrared radiation, and in visible light, about a hundred thousand times. That is, if you mentally place Betelgeuse and the Sun at the same distance, Betelgeuse would be a hundred thousand times brighter than the Sun. In the list of the most powerful known stars, Betelgeuse occupies approximately the twenty-fifth position (approximately, because the exact brightness of many hypergiants is not exactly known). If you place Betelgeuse at a standard distance of ten parsecs from the Earth (about 32 light years), then it would be visible during the day, and at night objects would cast shadows in its light. But it’s better not to put it there, because the radiation of a supergiant is such a thing that it’s better for living beings to look at from afar. It seems that the absence of nearby supergiants (of any color) is one of the conditions for life on Earth.
The surface temperature of Betelgeuse is three and a half thousand kelvins (well, ordinary degrees are also close to that). For a star, this is not much; Our Sun has a surface temperature of 5700 K, which is twice as hot. That is, Betelgeuse is a "cold" star, one of the coldest known stars. The temperature of a star determines its color, or rather the shade of its glow. Those mysterious people who manage to see the stars in color unequivocally define the color of Betelgeuse as pronouncedly reddish (see the epigraph). That is why Betelgeuse is called a red supergiant. It is not necessary to think that it really is bright red, like a poppy: rather, its surface is yellowish-orange.
Presumably, this is what the surface of Betelgeuse looks like.
I mentioned above that the apparent diameter of Betelgeuse is from 0.056 to 0.059 arcseconds. This variation is not due to inaccurate measurements. And due to the fact that the body of the star itself pulsates with an approximate period of several years, changing both size and brightness. It would be logical to assume that as the size decreases, the brightness of the star will also decrease, but in fact everything happens exactly the opposite: at the minimum size, Betelgeuse acquires maximum brightness. At maximum brightness, Betelgeuse turns out to be brighter than Rigel, whose magnitude is 0.18, that is, the brightest star in the constellation. Therefore, in terms of brilliance, Betelgeuse is fully entitled to the designation Alpha Orion.
In itself, this is not surprising: the heating of a star during compression is a common place in astrophysics (it occurs due to the transition of gravitational potential energy into kinetic energy, who knows the exact wording, correct me). But why is Betelgeuse so pulsating? What kind of processes are going on inside her? Nobody knows.
The short youth of a giant star
Remember we talked about how young Sirius is, only 250 million years old? So, Betelgeuse is a small child compared to Sirius: she is only 10 million years old! When it caught fire, dinosaurs had already died out on Earth long ago, mammals had already taken the main position on land, the continents had already almost taken on their current outlines, the youngest mountain systems (including the Himalayas) were being erected. Realize that the Ural Mountains are much older than Betelgeuse!
But unlike Sirius, which is not clear where it came from, it is very clear where Betelgeuse came from.
Orion is a unique constellation: the stars in it, not only for our eyes, but in reality are quite close to each other in space. And they are close in age too. The fact is that most of Orion is occupied by a giant nebula - the Molecular Cloud of Orion, in which intensive star formation processes are taking place (that is, it is a “stellar cradle”, besides, almost the closest to Earth). Young stars scatter from this nebula in all directions. Of these young, hot blue stars, exemplary peers, relatively close to the place of their birth, Orion consists.
But if all the other stars in Orion are hot to blue (which is typical for young stars), then why is Betelgeuse red?
Because it's very big.
The lifetime of a star is determined by how long it takes for hydrogen to completely turn into helium in the core of a star it must burn. But here again, the opposite is true: the larger and heavier the star, the higher the temperature in its core and the faster the thermonuclear reaction goes there. Since Betelgeuse was born heavier and larger than its peers Rigel, Bellatrix and other stars of Orion, the hydrogen in its core burned faster and burned out in just a few million years. And after the burning out of hydrogen in the core, the star enters the dying stage - the transformation into a red giant. In the case of Betelgeuse, it has evolved into a red supergiant.
That is, despite the fact that Betelgeuse is one of the youngest stars in the Universe in terms of age, it is already on the verge of death. Alas, large hot stars do not live very long, outliving their turbulent life in just a few million years. There are several more red hypergiants that have entered the last phase of their development, but they are all very far from us. Therefore, Betelgeuse provides a unique, albeit sad, opportunity to study the last phase of a star's life from a relatively close distance.
Betelgeuse is known to have shrunk in diameter by 15 percent over the past 15 years. This is a constant contraction, not associated with pulsations. Mathematical models of stars say that such a reduction in size is also a sign that the end of the star's evolution is approaching.
What will happen to Betelgeuse next? This is not the peaceful Sirius-Main, now Sirius B, who simply quietly threw off his scarlet shells and turned into a white dwarf. The mass of Betelgeuse is so great that it will have to throw off the shells in one of the grandest explosions that are known to the Universe - in the outbreak of a supernova.
And it will be the closest supernova to the Earth, perhaps for the entire time of the existence of the Earth. Precisely because there is not and has not been a single supergiant closer: supergiants are doomed to end their evolution in supernova explosions, supernova remnants are characteristic and easily identified, and so there is not a single one nearby.
When it will be? Betelgeuse will explode within the next millennium. Possibly tomorrow.
How will it look like? Instead of a shining point in the sky, a disk of dazzling brightness will appear, which will be visible during the day, and at night it will be possible to read by its light. This disk will slowly fade, and the night sky will probably return to normal in a few months. In place of Betelgeuse, a nebula of amazing beauty will appear, which will be visible to the naked eye for several years. Then nothing will be visible.
What will be left of Betelgeuse? No, not a white dwarf - it's too heavy for that. There will be a neutron star (pulsar) or a black hole.
How will this affect life on Earth? Most likely not. Betelgeuse is far enough from the Earth for the hard radiation from the supernova to dissipate into space without reaching the solar system, and what comes through is reflected by the solar magnetosphere. Only if the axis of rotation of Betelgeuse was directed directly to the Earth, then hard gamma radiation would painfully whip through the biosphere. But we know from Hubble photographs that Betelgeuse's axis of rotation is away from the Earth. So the heavenly fireworks can be admired from the Earth quite safely.
The same fate awaits Rigel, Bellatrix and the other bright stars of Orion over the next tens of millions of years. Before becoming a red supergiant, Betelgeuse was obviously a hot blue star like them. They will be replaced by young stars, still hidden from us in the depths of the Molecular Cloud of Orion.
So go and watch Betelgeuse while it's still shining. Heaven is not immutable.
largest visible star
On the right shoulder of Orion, in the crown of the Winter Hexagon, the beautiful Betelgeuse shines in the winter skies.
Constellation of Orion. Betelgeuse is a reddish-orange star in the upper left corner of the constellation.
This star is called alpha Orion for a reason, although the dazzling bluish Rigel - in the photo in the lower right corner - is brighter most of the time. Betelgeuse is in many ways a unique star that astronomers have been exploring for many years and discovering more and more interesting facts.
First, Betelgeuse is one of the largest stars in the universe. Its diameter is more than the diameter of the Sun by about a thousand times. Even the largest known star, VY Canis Major, is only twice the diameter of Betelgeuse (and therefore eight times the volume). So it is not in vain that this star bears the proud title of a red supergiant.
If it were in place of the Sun, it would almost fill the orbit of Saturn:
Only eight known stars (all red hypergiants) surpass Betelgeuse in volume, but they all look very dim in the earth's sky. The reason is simple: Betelgeuse is much closer than all of them.
Betelgeuse is 640 light-years away, which is very short on the scale of the Galaxy. Betelgeuse is the closest supergiant to us.
An interesting conclusion follows from this: Betelgeuse in the earth's sky has the largest apparent diameter of all stars (after the Sun, of course.)
It is clear that everything that is less than an arc minute in diameter is perceived by the human eye as a point. The angular diameters of absolutely all stars (except the Sun) are less than an arc minute, so they all look like dots. In fact, of course, all their angular diameters are different. The angular diameter of Betelgeuse was first determined in 1920 as 0.047 arcseconds, which was the largest angular diameter of a star then known. Since then, however, the star R Doradus, invisible in the northern hemisphere, has been discovered, the angular diameter of which turned out to be 0.057 arcseconds. But even in the southern hemisphere it is almost invisible: at maximum brightness it is hardly visible to the naked eye, and at minimum it can not be seen with every telescope. R Doradus is so cold that it emits mostly infrared radiation. But since then, the angular measurements have been refined, and for Betelgeuse, the apparent diameter is determined from 0.056 to 0.059 arcseconds, which restores to it the lost positions of the largest visible star. It's not so easy to push the queen of winter skies!
Not surprisingly, Betelgeuse was the first star for which disk photographs were taken. That is, on which the star looked not like a point, but a disk. (That the bright stars appear as disks in the above photograph is a convention of the image, which can only convey a difference in brightness by a difference in size.) The photo was taken by the Hubble Space Telescope in 1995.
Here is a historical UV image (NASA/ESA credit):
It is clear that the colors in the photograph are arbitrary: the redder, the colder. A bright spot near the center of the star is considered one of its poles, that is, the axis of rotation of Betelgeuse is directed almost towards us, but slightly to the side.
More recently, namely in July last (2009), new photographs of Betelgeuse were taken with the ground-based Very Large Telescope (VLT) in Chile. Here is one of them:
The resulting photos show that Betelgeuse has a tail. This tail stretches for six radii of Betelgeuse itself (comparable to the distance from the Sun to Neptune). What kind of tail it is, why it is there and what it means, scientists themselves do not yet know, although there are many assumptions.
Measuring Betelgeuse
It is interesting to give the main parameters of Betelgeuse. We will see that in almost all respects, Betelgeuse turns out to be one of the “winners” of the known Universe.
In diameter, as already mentioned, Betelgeuse exceeds the Sun by about a thousand times. It is very difficult to accurately determine the diameter and distance from the Sun of a single star, and no satellites have been found in Betelgeuse (although it is very possible that they are, they just cannot be seen next to such a hulk). But Betelgeuse is so huge that its diameter could be measured "directly", i.e. with the help of an interferometer - this operation could be applied to a very small number of stars, and Betelgeuse was the first.
In terms of mass, Betelgeuse exceeds the Sun by about 15 times (from 10 to 20 - to measure the mass of a single star is generally the aerobatics of astrometry, more precisely, it has not yet been possible). How can it be, a thousand times larger in diameter, which means that it is a billion times larger in volume, and only 15 times larger in mass, what is the density there? But this one. And if we take into account that the core of a star is much denser than its outer layers, then the outer layers of Betelgeuse are much rarer than anything that we can imagine, except for interstellar space, into which Betelgeuse, like almost any star, passes very gradually, i.e. it is impossible to determine exactly where the star ends and interstellar space begins. Nevertheless, fifteen solar masses is quite a lot for a star. Only 120 known stars are heavier than Betelgeuse.
How many times is Betelgeuse brighter than the Sun? One hundred thirty-five thousand times! True, this is taking into account infrared radiation, and in visible light, about a hundred thousand times. That is, if you mentally place Betelgeuse and the Sun at the same distance, Betelgeuse would be a hundred thousand times brighter than the Sun. In the list of the most powerful known stars, Betelgeuse occupies approximately the twenty-fifth position (approximately, because the exact brightness of many hypergiants is not exactly known). If you place Betelgeuse at a standard distance of ten parsecs from the Earth (about 32 light years), then it would be visible during the day, and at night objects would cast shadows in its light. But it’s better not to put it there, because the radiation of a supergiant is such a thing that it’s better for living beings to look at from afar. It seems that the absence of nearby supergiants (of any color) is one of the conditions for life on Earth.
The surface temperature of Betelgeuse is three and a half thousand kelvins (well, ordinary degrees are also close to that). For a star, this is not much; Our Sun has a surface temperature of 5700 K, which is twice as hot. That is, Betelgeuse is a "cold" star, one of the coldest known stars. The temperature of a star determines its color, or rather the shade of its glow. Those mysterious people who manage to see the stars in color unequivocally define the color of Betelgeuse as pronouncedly reddish (see the epigraph). That is why Betelgeuse is called a red supergiant. It is not necessary to think that it really is bright red, like a poppy: rather, its surface is yellowish-orange.
Presumably, this is what the surface of Betelgeuse looks like.
I mentioned above that the apparent diameter of Betelgeuse is from 0.056 to 0.059 arcseconds. This variation is not due to inaccurate measurements. And due to the fact that the body of the star itself pulsates with an approximate period of several years, changing both size and brightness. It would be logical to assume that as the size decreases, the brightness of the star will also decrease, but in fact everything happens exactly the opposite: at the minimum size, Betelgeuse acquires maximum brightness. At maximum brightness, Betelgeuse turns out to be brighter than Rigel, whose magnitude is 0.18, that is, the brightest star in the constellation. Therefore, in terms of brilliance, Betelgeuse is fully entitled to the designation Alpha Orion.
In itself, this is not surprising: the heating of a star during compression is a common place in astrophysics (it occurs due to the transition of gravitational potential energy into kinetic energy, who knows the exact wording, correct me). But why is Betelgeuse so pulsating? What kind of processes are going on inside her? Nobody knows.
The short youth of a giant star
Remember we talked about how young Sirius is, only 250 million years old? So, Betelgeuse is a small child compared to Sirius: she is only 10 million years old! When it caught fire, dinosaurs had already died out on Earth long ago, mammals had already taken the main position on land, the continents had already almost taken on their current outlines, the youngest mountain systems (including the Himalayas) were being erected. Realize that the Ural Mountains are much older than Betelgeuse!
But unlike Sirius, which is not clear where it came from, it is very clear where Betelgeuse came from.
Orion is a unique constellation: the stars in it, not only for our eyes, but in reality are quite close to each other in space. And they are close in age too. The fact is that most of Orion is occupied by a giant nebula - the Molecular Cloud of Orion, in which intensive star formation processes are taking place (that is, it is a “stellar cradle”, besides, almost the closest to Earth). Young stars scatter from this nebula in all directions. Of these young, hot blue stars, exemplary peers, relatively close to the place of their birth, Orion consists.
But if all the other stars in Orion are hot to blue (which is typical for young stars), then why is Betelgeuse red?
Because it's very big.
The lifetime of a star is determined by how long it takes for hydrogen to completely convert to helium in the star's core. (people, educational program about why the stars are burning, do you need to write?) It would seem that the larger and heavier the star, the more hydrogen it contains, and the longer it should burn. But here again, the opposite is true: the larger and heavier the star, the higher the temperature in its core and the faster the thermonuclear reaction goes there. Since Betelgeuse was born heavier and larger than its peers Rigel, Bellatrix and other stars of Orion, the hydrogen in its core burned faster and burned out in just a few million years. And after the burning out of hydrogen in the core, the star enters the dying stage - the transformation into a red giant. In the case of Betelgeuse, it has evolved into a red supergiant.
That is, despite the fact that Betelgeuse is one of the youngest stars in the Universe in terms of age, it is already on the verge of death. Alas, large hot stars do not live very long, outliving their turbulent life in just a few million years. There are several more red hypergiants that have entered the last phase of their development, but they are all very far from us. Therefore, Betelgeuse provides a unique, albeit sad, opportunity to study the last phase of a star's life from a relatively close distance.
Betelgeuse is known to have shrunk in diameter by 15 percent over the past 15 years. This is a constant contraction, not associated with pulsations. Mathematical models of stars say that such a reduction in size is also a sign that the end of the star's evolution is approaching.
What will happen to Betelgeuse next? This is not the peaceful Sirius-Main, now Sirius B, who simply quietly threw off his scarlet shells and turned into a white dwarf. The mass of Betelgeuse is so great that it will have to throw off the shells in one of the grandest explosions that are known to the Universe - in the outbreak of a supernova.
And it will be the closest supernova to the Earth, perhaps for the entire time of the existence of the Earth. Precisely because there is not and has not been a single supergiant closer: supergiants are doomed to end their evolution in supernova explosions, supernova remnants are characteristic and easily identified, and so there is not a single one nearby.
When it will be? Betelgeuse will explode within the next millennium. Possibly tomorrow.
How will it look like? Instead of a shining point in the sky, a disk of dazzling brightness will appear, which will be visible during the day, and at night it will be possible to read by its light. This disk will slowly fade, and the night sky will probably return to normal in a few months. In place of Betelgeuse, a nebula of amazing beauty will appear, which will be visible to the naked eye for several years. Then nothing will be visible.
What will be left of Betelgeuse? No, not a white dwarf - it's too heavy for that. There will be a neutron star (pulsar) or a black hole.
How will this affect life on Earth? Most likely not. Betelgeuse is far enough from the Earth for the hard radiation from the supernova to dissipate into space without reaching the solar system, and what comes through is reflected by the solar magnetosphere. Only if the axis of rotation of Betelgeuse was directed directly to the Earth, then hard gamma radiation would painfully whip through the biosphere. But we know from Hubble photographs that Betelgeuse's axis of rotation is away from the Earth. So the heavenly fireworks can be admired from the Earth quite safely.
The same fate awaits Rigel, Bellatrix and the other bright stars of Orion over the next tens of millions of years. Before becoming a red supergiant, Betelgeuse was obviously a hot blue star like them. They will be replaced by young stars, still hidden from us in the depths of the Molecular Cloud of Orion.
Other photos of the star can be found.
Betelgeuse (α Orioni) is a bright star in the constellation Orion. A red supergiant, a semi-regular variable star whose brightness varies from 0.2 to 1.2 magnitudes and averages about 0.7 m. The red color of the star, easily visible when observed with the naked eye, corresponds to the color index B-V = 1.86 m. The minimum luminosity of Betelgeuse is 80 thousand times greater than the luminosity of the Sun, and the maximum is 105 thousand times. The distance to the star is, according to various estimates, from 495 to 640 light years. This is one of the largest stars known to astronomers: if it were placed in the place of the Sun, then at a minimum size it would fill the orbit of Mars, and at a maximum size it would reach the orbit of Jupiter.
The angular diameter of Betelgeuse, according to modern estimates, is about 0.055 arc seconds. If we take the distance to Betelgeuse equal to 570 light years, then its diameter will exceed the diameter of the Sun by about 950-1000 times. The mass of Betelgeuse is approximately 17 solar masses.
Comparison of the sizes of the Sun and Betelgeuse
Presumably, the name comes from the distorted Arabic “Yad al Jawza” (“twin’s hand” or even his “armpit”), which in medieval Latin, due to a copyist’s mistake who did not know the intricacies of translation from Arabic, was first transformed into Bedalgeuze, and then gradually into the present day. famous Betelgeuse.
Do not confuse the modern constellation Gemini with the Arabic one. Orion, in which Betelgeuse is located, was part of Gemini among the Arabs.
An interesting fact is that over 16 years of observations since 1993, the radius of Betelgeuse has decreased by as much as 15 percent, while its brightness has not changed. Scientists have not yet given a clear answer why this happened. Versions are being put forward both about the inaccuracies of the observations of the star, and that perhaps it has an irregular shape and simply turned its other side towards us during the observations. Since Betelgeuse is as much as 570 light-years distant from the Sun, it is not possible to collect more accurate data on its characteristics at the moment.
The future of the star is also very vague. Perhaps the fate of a supernova awaits her, or perhaps this red supergiant will be lucky and she will throw off her shell in the form of a planetary nebula, and she herself will turn into a white dwarf. If the star is destined to explode, then a supernova comparable in brightness to the Moon will be observed on Earth for several months, and then the star will disappear forever for earthlings, but after centuries a nebula will become visible in this place.
However, if one of Betelgeuse's poles points towards Earth, there will be more tangible impacts. A stream of gamma rays and other cosmic particles will be sent to the Earth. There will be strong auroras and possibly a measurable decrease in the amount of ozone in the ozone layer, with subsequent adverse effects on life on the planet. In the case of such an orientation with respect to the solar system, the flash will also be many times brighter than if the axis of the star is directed away from us.
In 1980, Shu-ren, Jianming and Jin-yi found Chinese reports dating back to the 1st century BC during excavations. e., from which it follows that the color of Betelgeuse is white or yellow. At the same time, Ptolemy in 150 AD. e. describes it as a red star. Fang Lizhi, a Chinese astrophysicist, suggested that Betelgeuse may have evolved into a red giant star at that time. Stars are known to change their color from white to yellow to red after they use up the hydrogen in their cores. Shu-ren suggested that Betelgeuse may have changed its color when she shed the shell of dust and gas that is visible even now and is still expanding. Thus, if their version is correct, it is unlikely that Betelgeuse will soon go supernova, because the star usually remains a red giant for tens of thousands of years.