What do you know about supernovae? Surely you will say that a supernova is a grandiose explosion of a star, in the place of which a neutron star or a black hole remains.

However, in fact, not all supernovae are the final stage in the life of massive stars. The modern classification of supernova explosions, in addition to explosions of supergiants, also includes some other phenomena.

New and supernova

The term "supernova" migrated from the term "new star". "New" called the stars that appeared in the sky almost from scratch, after which they gradually faded away. The first "new" ones are known from the Chinese chronicles dating back to the second millennium BC. Interestingly, supernovae were often found among these novae. For example, it was Tycho Brahe who observed the supernova in 1571, who later coined the term "new star". Now we know that in both cases we are not talking about the birth of new luminaries in the literal sense.

New and supernovae indicate a sharp increase in the brightness of a star or group of stars. As a rule, before people did not have the opportunity to observe the stars that generated these outbreaks. These were too faint objects for the naked eye or the astronomical instrument of those years. They were observed already at the moment of the flash, which naturally resembled the birth of a new star.

Despite the similarity of these phenomena, today there is a sharp difference in their definitions. The peak luminosity of supernovae is thousands and hundreds of thousands times greater than the peak luminosity of new stars. This discrepancy is explained by the fundamental difference in the nature of these phenomena.

The birth of new stars

New flares are thermonuclear explosions occurring in some close star systems. Such systems also consist of a larger companion star (main sequence star, subgiant or ). The powerful gravity of the white dwarf pulls matter from the companion star, resulting in the formation of an accretion disk around it. Thermonuclear processes occurring in the accretion disk sometimes lose stability and become explosive.

As a result of such an explosion, the brightness of the stellar system increases in thousands, and even hundreds of thousands of times. This is how a new star is born. An object hitherto dim, and even invisible to the earthly observer, acquires a noticeable brightness. As a rule, such an outbreak reaches its peak in just a few days, and can fade for years. Quite often, such outbursts are repeated in the same system every few decades; are periodic. There is also an expanding shell of gas around the new star.

Supernova explosions have a completely different and more diverse nature of their origin.

Supernovae are usually divided into two main classes (I and II). These classes can be called spectral, since they are distinguished by the presence and absence of hydrogen lines in their spectra. Also, these classes are noticeably different visually. All class I supernovae are similar both in terms of the power of the explosion and in the dynamics of the change in brightness. Supernovae of class II are very diverse in this respect. The power of their explosion and the dynamics of brightness changes lie in a very wide range.

All class II supernovae are generated by gravitational collapse in the interiors of massive stars. In other words, this is the same, familiar to us, explosion of supergiants. Among the supernovae of the first class, there are those whose explosion mechanism is more similar to the explosion of new stars.

Death of the supergiants

Supernovae are stars whose mass exceeds 8-10 solar masses. The nuclei of such stars, having exhausted hydrogen, proceed to thermonuclear reactions with the participation of helium. Having exhausted helium, the core proceeds to the synthesis of ever heavier elements. More and more layers are being created in the bowels of a star, each of which has its own type of thermonuclear fusion. At the final stage of its evolution, such a star turns into a "layered" supergiant. Iron synthesis occurs in its core, while helium synthesis from hydrogen continues closer to the surface.

The fusion of iron nuclei and heavier elements occurs with the absorption of energy. Therefore, having become iron, the core of the supergiant is no longer able to release energy to compensate for gravitational forces. The core loses its hydrodynamic balance and begins to erratic compression. The remaining layers of the star continue to maintain this balance until the core shrinks to a certain critical size. Now the rest of the layers and the star as a whole lose their hydrodynamic equilibrium. Only in this case it is not compression that “wins”, but the energy released during the collapse and further random reactions. There is a reset of the outer shell - a supernova explosion.

class differences

The different classes and subclasses of supernovae are explained by the way the star was before the explosion. For example, the absence of hydrogen in class I supernovae (subclasses Ib, Ic) is a consequence of the fact that the star itself did not have hydrogen. Most likely, part of its outer shell was lost during evolution in a close binary system. The spectrum of subclass Ic differs from Ib in the absence of helium.

In any case, supernovae of such classes occur in stars that do not have an outer hydrogen-helium shell. The rest of the layers lie within rather strict limits of their size and mass. This is explained by the fact that thermonuclear reactions replace each other with the onset of a certain critical stage. That is why explosions of class Ic and Ib stars are so similar. Their peak luminosity is about 1.5 billion times that of the Sun. They reach this luminosity in 2-3 days. After that, their brightness weakens 5-7 times in a month and slowly decreases in subsequent months.

Type II supernova stars had a hydrogen-helium shell. Depending on the mass of the star and its other features, this shell can have different boundaries. This explains the wide range in the characters of supernovae. Their brightness can vary from tens of millions to tens of billions of solar luminosities (excluding gamma-ray bursts - see below). And the dynamics of changes in brightness has a very different character.

white dwarf transformation

Flares constitute a special category of supernovae. This is the only class of supernovae that can occur in elliptical galaxies. This feature suggests that these outbreaks are not the product of the death of supergiants. Supergiants do not survive until the moment when their galaxies "grow old", i.e. become elliptical. Also, all flashes of this class have almost the same brightness. Because of this, type Ia supernovae are the "standard candles" of the Universe.

They emerge in a very different pattern. As noted earlier, these explosions are somewhat similar in nature to new explosions. One of the schemes for their origin suggests that they also originate in a close system of a white dwarf and its companion star. However, unlike new stars, a detonation of a different, more catastrophic type occurs here.

As it “devours” its companion, the white dwarf increases in mass until it reaches the Chandrasekhar limit. This limit, approximately equal to 1.38 solar masses, is the upper limit of the mass of a white dwarf, after which it turns into a neutron star. Such an event is accompanied by a thermonuclear explosion with a colossal release of energy, many orders of magnitude greater than a conventional new explosion. The practically unchanged value of the Chandrasekhar limit explains such a small discrepancy in the brightness of various flares of this subclass. This brightness is almost 6 billion times greater than the solar luminosity, and the dynamics of its change is the same as for class Ib, Ic supernovae.

Hypernova Explosions

Hypernovae are bursts whose energy is several orders of magnitude higher than the energy of typical supernovae. That is, in fact, they are hypernovae are very bright supernovae.

As a rule, an explosion of supermassive stars, also called hypernovae, is considered. The mass of such stars starts from 80 and often exceeds the theoretical limit of 150 solar masses. There are also versions that hypernovae can be formed during the annihilation of antimatter, the formation of a quark star, or the collision of two massive stars.

Hypernovae are noteworthy in that they are the main cause of, perhaps, the most energy-intensive and rarest events in the Universe - gamma-ray bursts. The duration of gamma-ray bursts ranges from hundredths of a second to several hours. But most often they last 1-2 seconds. In these seconds, they emit energy similar to the energy of the Sun for all 10 billion years of its life! The nature of gamma-ray bursts is still mostly questionable.

Ancestors of life

Despite all their catastrophic nature, supernovae can rightfully be called the progenitors of life in the Universe. The power of their explosion pushes the interstellar medium to form gas and dust clouds and nebulae, in which stars are subsequently born. Another feature of them is that supernovae saturate the interstellar medium with heavy elements.

It is supernovae that generate all chemical elements that are heavier than iron. After all, as noted earlier, the synthesis of such elements requires energy. Only supernovae are capable of "charging" compound nuclei and neutrons for the energy-intensive production of new elements. The kinetic energy of the explosion carries them through space along with the elements formed in the bowels of the exploded star. These include carbon, nitrogen and oxygen and other elements without which organic life is impossible.

supernova observation

Supernova explosions are extremely rare phenomena. In our galaxy, which contains over a hundred billion stars, there are only a few flares per century. According to chronicle and medieval astronomical sources, over the past two thousand years, only six supernovae visible to the naked eye have been recorded. Modern astronomers have never seen supernovae in our galaxy. The closest one happened in 1987 in the Large Magellanic Cloud, one of the satellites of the Milky Way. Every year, scientists observe up to 60 supernovae occurring in other galaxies.

It is because of this rarity that supernovae are almost always observed already at the time of the outbreak. The events preceding it were almost never observed, so the nature of supernovae is still largely mysterious. Modern science is not able to accurately predict supernovae. Any candidate star is capable of flaring up only after millions of years. The most interesting in this regard is Betelgeuse, which has a very real opportunity to illuminate the earthly sky in our lifetime.

Universal outbreaks

Hypernova explosions are even rarer. In our galaxy, such an event occurs once every hundreds of thousands of years. However, gamma-ray bursts generated by hypernovae are observed almost daily. They are so powerful that they are recorded from almost all corners of the universe.

For example, one of the gamma-ray bursts, located 7.5 billion light years away, could be seen with the naked eye. To happen in the Andromeda galaxy, the earth's sky for a couple of seconds was illuminated by a star with the brightness of the full moon. If it happened on the other side of our galaxy, a second Sun would appear against the background of the Milky Way! It turns out that the brightness of the flash is quadrillion times brighter than the Sun and millions of times brighter than our Galaxy. Considering that there are billions of galaxies in the Universe, it is not surprising why such events are recorded daily.

Impact on our planet

It is unlikely that supernovae can pose a threat to modern humanity and in any way affect our planet. Even the explosion of Betelgeuse will only light up our sky for a few months. However, they certainly have had a decisive influence on us in the past. An example of this is the first of five mass extinctions on Earth that occurred 440 million years ago. According to one version, the cause of this extinction was a gamma-ray flash that occurred in our Galaxy.

More remarkable is the completely different role of supernovae. As already noted, it is supernovae that create the chemical elements necessary for the emergence of carbon-based life. The terrestrial biosphere was no exception. The solar system formed in a gas cloud that contained fragments of former explosions. It turns out that we all owe our appearance to a supernova.

Moreover, supernovae continued to influence the evolution of life on Earth. By increasing the radiation background of the planet, they forced organisms to mutate. Don't forget about major extinctions. Surely supernovae more than once "made adjustments" to the earth's biosphere. After all, if there weren’t those global extinctions, completely different species would now dominate the Earth.

The scale of stellar explosions

To visually understand what kind of energy supernova explosions have, let's turn to the equation of the equivalent of mass and energy. According to him, every gram of matter contains a colossal amount of energy. So 1 gram of a substance is equivalent to the explosion of an atomic bomb exploded over Hiroshima. The energy of the tsar bomb is equivalent to three kilograms of matter.

Every second during thermonuclear processes in the bowels of the Sun, 764 million tons of hydrogen turns into 760 million tons of helium. Those. every second the Sun radiates energy equivalent to 4 million tons of matter. Only one two billionth of all the energy of the Sun reaches the Earth, which is equivalent to two kilograms of mass. Therefore, they say that the explosion of the tsar bomb could be observed from Mars. By the way, the Sun delivers several hundred times more energy to Earth than humanity consumes. That is, in order to cover the annual energy needs of all modern humanity, only a few tons of matter need to be converted into energy.

Given the above, imagine that the average supernova at its peak "burns" quadrillions of tons of matter. This corresponds to the mass of a large asteroid. The total energy of a supernova is equivalent to the mass of a planet or even a low-mass star. Finally, a gamma-ray burst in seconds, or even fractions of a second of its life, splashes out energy equivalent to the mass of the Sun!

Such different supernovae

The term "supernova" should not be associated solely with the explosion of stars. These phenomena are perhaps as diverse as the stars themselves. Science has yet to understand many of their secrets.

A supernova explosion is an event of incredible proportions. In fact, a supernova explosion means the end of its existence or, which also takes place, rebirth in the form of a black hole or a neutron star. The end of a supernova's life is always accompanied by an explosion of great force, during which the star's matter is ejected into space at an incredible speed and over great distances.

A supernova explosion lasts only a few seconds, but during this short period of time, a phenomenal amount of energy is released. So, for example, a supernova explosion can emit 13 times more light than an entire galaxy consisting of billions of stars, and the amount of radiation released in the form of gamma and X-ray waves in seconds is many times greater than in billions of years of life.

Since supernova explosions do not last very long, especially taking into account the cosmic scale and magnitude, they are known mainly by the consequences. Such consequences are huge gaseous nebulae, which continue to glow and expand in space for a very long time after the explosion.

Perhaps the most famous nebula formed as a result of a supernova explosion is crab nebula. Thanks to the chronicles of ancient Chinese astronomers, it is known that it arose after the explosion of a star in the constellation Taurus in 1054. As you might guess, the flash was so bright that it could be observed with the naked eye. Now, the Crab Nebula can be seen on a dark night with ordinary binoculars.

The Crab Nebula is still expanding at a speed of 1,500 km per second. At the moment, its size exceeds 5 light years.

The photo above is a compilation of three images taken in three different spectra: X-ray (Chandra telescope), infrared (Spitzer telescope) and conventional optical (). X-rays are represented in blue, and their source is a pulsar - an incredibly dense star formed after the death of a supernova.

The Simeis 147 Nebula is one of the largest nebulae known at the moment. A supernova that exploded about 40,000 years ago created a 160 light-year nebula. It was discovered by Soviet scientists G. Shayon and V. Gaza in 1952 at the Simeiz observatory of the same name.

The photo shows the last supernova explosion that could be observed with the naked eye. Occurred in 1987 in the Large Magellanic Cloud galaxy at a distance of 160,000 light-years from us. Of great interest are unusual rings in the form of the number 8, about the true nature of which scientists are still making only assumptions.

The Medusa Nebula in the Gemini constellation has not been studied as well, but is very popular due to its unprecedented beauty and a large companion star that periodically changes its brightness.

A supernova explosion is a truly cosmic phenomenon. In fact, this is an explosion of colossal power, as a result of which the star either ceases to exist at all, or passes into a qualitatively new form - in the form of a neutron star or a black hole. In this case, the outer layers of the star are ejected into space. Scattering at high speed, they give rise to beautiful glowing nebulae.

The Crab Nebula gained notoriety in 1758 when astronomers were awaiting the return of Halley's Comet. Charles Messier, the famous "comet catcher" of that time, was looking for a tailed guest among the horns of Taurus, where it was predicted. But instead, the astronomer discovered an elongated nebula, which confused him so much that he mistook it for a comet. In the future, in order to avoid confusion, Messier decided to catalog all the nebulous objects in the sky. The Crab Nebula is catalog number 1. This image of the Crab Nebula was taken by the Hubble Space Telescope. It shows many details: gas fibers, knots, condensations. Today, the nebula is expanding at a speed of about 1,500 km/s, and the change in its size is visible in photographs taken just a few years apart. The total dimensions of the Crab Nebula exceed 5 light years.

The Crab Nebula (or M1 according to the catalog of C. Messier) is one of the most famous space objects. The point here is not its brightness or special beauty, but the role that the Crab Nebula has played in the history of science. The nebula is the remnant of a supernova explosion that occurred in 1054. Mentions of the appearance of a very bright star in this place have been preserved in Chinese chronicles. M1 is in the constellation Taurus, next to the star ζ; on dark transparent nights it can be seen with binoculars.


The famous object Cassiopeia A, the brightest source of radio emission in the sky. This is the remnant of a supernova that erupted around 1667 in the constellation of Cassiopeia. Strange, but we do not find any mention of a bright star in the annals of the second half of the 17th century. Probably, in the optical range, its radiation was greatly attenuated by interstellar dust. As a result of the last observed supernova in our galaxy, there is still a Kepler supernova.


Crab nebula in optics, thermal and X-rays. At the center of the nebula is a pulsar, a superdense neutron star that emits radio waves and generates X-rays in its surrounding matter (X-rays shown in blue). Observations of the Crab Nebula at various wavelengths have given astronomers fundamental information about neutron stars, pulsars, and supernovae. This image is a combination of three images taken by the Chandra, Hubble and Spitzer space telescopes.


The remnant of Tycho's supernova. A supernova erupted in 1572 in the constellation of Cassiopeia. The bright star was observed by the Dane Tycho Brahe, the best astronomer-observer of the pre-telescopic era. The book written by Brahe in the wake of this event was of tremendous ideological significance, because at that time it was believed that the stars were unchanged. Already in our time, astronomers have been hunting for this nebula with telescopes for a long time, and in 1952 they discovered its radio emission. The first photograph in optics was taken only in the 1960s.


Supernova remnant in the constellation Sails. Most of the supernovae in our Galaxy appear in the plane of the Milky Way, since it is here that massive stars are born and spend their short lives. The fibrous supernova remnants are hard to see in this image due to the abundance of stars and red hydrogen nebulae, but the expanding spherical shell can still be identified by its greenish glow. A supernova in Sails broke out about 11-12 thousand years ago. During the outburst, the star ejected a huge mass of matter into space, but did not completely collapse: in its place was a pulsar, a neutron star emitting radio waves.


The Pencil Nebula (NGC 2736), part of a supernova shell in the constellation Vela. In fact, the nebula is a shock wave propagating in space at a speed of half a million kilometers per hour (in the picture it flies from the bottom up). Several thousand years ago, this speed was even higher, but the pressure of the surrounding interstellar gas, no matter how insignificant it was, slowed down the expanding shell of the supernova.


Close-up of NGC 6962 or Eastern Veil. Another name for this object is the Network Nebula


The Simeiz 147 Nebula (aka Sh 2-240) is a huge remnant of a supernova explosion, located on the border of the constellations Taurus and Auriga. The nebula was discovered in 1952 by Soviet astronomers G. A. Shain and V. E. Gaze at the Simeiz observatory in the Crimea. The explosion occurred about 40,000 years ago, during which time the expanding material occupied an area of ​​\u200b\u200bthe sky 36 times the area of ​​​​the full moon! The actual dimensions of the nebula are an impressive 160 light years, and the distance to it is estimated at 3000 light years. years. A distinctive feature of the object is long curved gas filaments, which gave the nebula the name Spaghetti.


The Medusa Nebula, another well-known supernova remnant, lies in the constellation Gemini. The distance to this nebula is poorly known and is probably about 5,000 light-years. The date of the explosion is also known very approximately: 3 - 30 thousand years ago. The bright star on the right is an interesting variable, eta Gemini, which can be observed (and studied for changes in its brightness) with the naked eye.


The last of the supernova explosions observed with the naked eye occurred in 1987 in a nearby galaxy, the Large Magellanic Cloud. The brightness of supernova 1987A reached magnitude 3, which is quite a lot considering the colossal distance to it (about 160,000 light years); The progenitor of the supernova was a blue hypergiant star. After the explosion, an expanding nebula and mysterious rings in the form of the number 8 remained in place of the star. Scientists suggest that the reason for their appearance may be the interaction of the stellar wind of the predecessor star with the gas ejected during the explosion

MOSCOW, February 13 - RIA Novosti. Scientists for the first time managed to see a supernova explosion in the first hours after its birth and to follow how the shock wave “accelerates” electrons in the remains of an ejected star, according to an article published in the journal Nature Physics.

"Supernovae flare so brightly that they can be seen from the other side of the universe, but they usually have time to destroy some of their own emissions at the moment when we notice them. Therefore, these observations are so valuable - we first saw the gaseous shell surrounding a dying star" , — commented on the study Norbert Langer (Norbert Langer) from the University of Bonn (Germany).

The last flash of a star

Supernovae flare as a result of the gravitational collapse of massive stars, when the star's heavy core contracts and creates a rarefaction wave that ejects the light matter of the star's outer layers into outer space. As a result, a luminous gaseous nebula is formed, which continues to expand for some time after the explosion. Supernovae of the first type are formed as a result of the explosion of a binary system of a white dwarf and a more massive star, and the more common outbreaks of the second type are the result of the explosion of giant stars.

Scientists: "Nobel supernova" threw a star out of the GalaxyAs scientists today believe, most of the hypervelocity stars are born as a result of interaction with a black hole, and they believe that the study of the orbits of hypervelocity stars will make it possible to judge the properties of black holes and even dark matter.

In recent years, scientists have recorded hundreds of new supernovae and actively studied their outbreaks, which helped us learn a lot about how elements heavier than iron are born, how the solar system could have arisen, and what role supernovae play in the evolution of galaxies and the birth of stars in them. However, the main secrets of supernovae remain a mystery to astronomers, as they are usually found a few days after the outbreak occurs, and when the shock wave propagating from the center of the supernova through its entire nebula has already had time to destroy part of the outer shells of the dead star.

Ofer Yaron of the Weizmann Institute of Science in Rehovot, Israel, has taken the first step towards unraveling these mysteries by obtaining photographs and the first spectral data from supernova iPTF 13dqy, which exploded in the constellation Pegasus in the galaxy NGC 7610 just three hours after its birth. It is located relatively close to the Milky Way, only 160 million light years away, which allowed scientists to study this flare in detail using the Swift telescope and the ground-based Palomar Observatory.

iPTF 13dqy itself is a type 2 supernova that exploded in the night sky on October 6, 2013. Due to the fact that it was quickly discovered, scientists were able to examine the gaseous shells dropped by its progenitor in the last few million years of life before death.

Scientists expect a supernova explosion in the Milky Way in the next 50 yearsAstronomers plan to catch the right moment with the help of a neutrino detector. A supernova emits them from the very beginning of the explosion, but at the same time it can flash in infrared or visible light only after a few minutes, hours or days.

supernova bulb

These shells, as scientists say, are the source of the most powerful flashes generated by a supernova. The gas in them collides with a shock wave emanating from the bowels of a dying star, and is heated to superhigh temperatures, as a result of which electrons "escape" from atoms and generate powerful beams of ultraviolet and other types of electromagnetic waves. The strength, duration and other characteristics of this radiation depend on the structure of the shells of the former star, thanks to which Yaron and his colleagues were able to "see" its structure by observing fluctuations in the brightness of individual lines in the spectrum of iPTF 13dqy in the first hours of its existence.

© Ofer Yaron

These observations showed that the diameter of this ball of gas and dust is quite large - about 20 light minutes, or about 360 million kilometers. This distance corresponds to about the same distance as the main asteroid belt between Jupiter and Mars in relation to the Sun. All traces of this structure should have disappeared approximately 10 days after the explosion of the star and the shock wave reaching the farthest corners of its gas and dust "cocoon".

The existence of this structure of gas and dust indicates that in the last year of its life, the dying star ejected record-breaking volumes of gas and dust into the surrounding space, losing about 0.1% of the mass of the Sun during this time. This was possible, according to scientists, only if the interior of the star was extremely unstable in the last days of its life.

The presence of such a relationship between emissions and processes inside a star that lead to its explosion can help astrophysicists more accurately predict how supernovae explode and how fast the closest candidate to Earth will explode - the red supergiant Betelgeuse in the constellation of Orion, which is only 640 light years. As the researchers hope, the discovery of other early supernovae will clarify this issue.

We have already seen that, unlike the Sun and other stationary stars, physical variable stars change in size, photosphere temperature, and luminosity. Among the various types of nonstationary stars, novae and supernovae are of particular interest. In fact, these are not newly appeared stars, but pre-existing ones, which attracted attention with a sharp increase in brightness.

During the outbursts of new stars, the brightness increases thousands and millions of times over a period of several days to several months. Stars have been known to re-flare as new ones. According to modern data, new stars are usually part of binary systems, and the outbursts of one of the stars occur as a result of the exchange of matter between the stars that form the binary system. For example, in the "white dwarf - ordinary star (of low luminosity)" system, explosions that cause the appearance of a new star can occur when gas falls from an ordinary star onto a white dwarf.

Even more grandiose are the bursts of supernovae, the brightness of which suddenly increases by about 19 m! At maximum brightness, the radiating surface of the star approaches the observer at a speed of several thousand kilometers per second. The pattern of supernova explosions suggests that supernovae are exploding stars.

Supernova explosions release enormous energy over the course of several days - about 10 41 J. Such colossal explosions occur at the final stages of the evolution of stars, the mass of which is several times greater than the mass of the Sun.

At maximum brightness, one supernova can shine brighter than a billion stars like our Sun. During the most powerful explosions of some supernovae, matter can be ejected at a speed of 5000 - 7000 km / s, the mass of which reaches several solar masses. The remnants of the shells thrown off by supernovae are visible for a long time as expanding gas.

Not only the remnants of supernova shells were found, but also what was left of the central part of the once exploded star. Such “stellar remnants” turned out to be amazing sources of radio emission, which were named pulsars. The first pulsars were discovered in 1967.

Some pulsars have an amazingly stable repetition rate of radio emission pulses: the pulses repeat at exactly the same time intervals, measured with an accuracy exceeding 10 -9 s! Open pulsars are located at distances not exceeding hundreds of parsecs from us. It is assumed that pulsars are rapidly rotating superdense stars with radii of about 10 km and masses close to the mass of the Sun. Such stars consist of densely packed neutrons and are called neutron stars. Only part of the time of their existence, neutron stars manifest themselves as pulsars.

Supernova explosions are rare events. Over the past millennium, only a few supernova explosions have been observed in our star system. Of these, the following three have been most reliably established: the outbreak of 1054 in the constellation Taurus, in 1572 in the constellation of Cassiopeia, in 1604 in the constellation of Ophiuchus. The first of these supernovae was described as a “guest star” by Chinese and Japanese astronomers, the second by Tycho Brahe, and the third was observed by Johannes Kepler. The brightness of the supernovas of 1054 and 1572 exceeded the brightness of Venus, and these stars were visible during the day. Since the invention of the telescope (1609), not a single supernova has been observed in our star system (it is possible that some outbreaks have gone unnoticed). When it became possible to explore other star systems, they often began to discover new and supernovae stars.

On February 23, 1987, a supernova exploded in the Large Magellanic Cloud (the constellation of the Dorado) - the largest satellite of our Galaxy. For the first time since 1604, a supernova could be seen even with the naked eye. Before the outbreak, a star of the 12th magnitude was in place of the supernova. The star reached its maximum brightness of 4 m in early March, and then began to slowly fade. Scientists who observed the supernova with the help of telescopes of the largest ground-based observatories, the Astron orbital observatory and X-ray telescopes on the Kvant module of the Mir orbital station managed to trace the entire process of the outbreak for the first time. The observations were carried out in different ranges of the spectrum, including the visible optical range, ultraviolet, X-ray and radio ranges. Sensational reports appeared in the scientific press about the registration of neutrino and, possibly, gravitational radiation from an exploded star. The models of the structure of the star in the phase preceding the explosion were refined and enriched with new results.