Tamerlane and Bereke Mir Seyid Bereke. Who is he? Where did it come from? And why is there so little official history preserved significant facts from the life of the sheikh? Why did Timur’s warriors go into battle with the cry: Allayar! What does the concept of Allayar mean? .. The answers to these and many other questions are stored in the treatise “Omnipotence”, written by Mir Seyid Bereke himself, which today, unfortunately, is hidden from the general public in the Vatican library. So, a little about the treatise “Omnipotence”, which begins with the words: “After Atlantis was destroyed for all the evil it had done, there were few people left on Earth…. And under the spiritual leadership of the Allat sisters, the Golden Millennium was created and existed for 1000 years... There was a matriarchy or it was also called the Holy Age... There was united people, was common language and a single sign... Time passed and after the Allat sisters left, AllatKhyara remained - these are those who were next to the Allat sisters... They helped them and learned from them. And they remained the keepers of Knowledge... For some time they tried to help people reach agreement among themselves... But ultimately the number of people increased, this led to the fact that clans and settlements began to form, people began to compete with each other. The AllatKhyaRa Order first became mixed, that is, men began to join it, and ultimately they completely replaced women. Patriarchy came, which also split. Archons were formed on the one hand, Arhats on the other hand, and the keepers of this Knowledge remained... These keepers were called AllatKhyaRa... They passed on the Knowledge, as a rule, from father to son, or from grandfather to grandson... Gradually AllatKhyaRa (Going to life) changed to AllayaRa (favorite God or follower of God)…” Tamerlane’s warriors went into battle with the words of Allayar. Why? Because they went into battle for Bereke, they felt his strength, his power, his support. In fact, they went into battle not for Timur, but for Seyid Mir Bereke... Sheikh originally from Mecca... A direct descendant of the Prophet Muhammad (peace be upon him)... Guardian of Knowledge... In fact, Timur became Tamerlane thanks to the support that his spiritual mentor provided him... Buried Tamerlane at the feet of Bereke's grave... The Vatican at one time provided some knowledge from Bereke's treatise “Omnipotence”, which, among other things, also talked about how to control the masses and how to control matter - to Hitler and the Nazi elite. How clear example- this is what Hitler did to the crowd during speeches. (This is not his oratorical talent, as history tells us today, but the knowledge from Seyyid Mir Bereke’s treatise, due to the use of which some women even experienced orgasm during Hitler’s speeches). This is another proof criminal activity The Vatican, its anti-human activities. After 200 years, Sufi Allayar tried to convey this knowledge in his treatise “On Eternity,” having considerably distorted it. The photo was taken in Samarkand, the tomb of Amir Timur. Gur Emir.
August 29th, 2013 , 10:33 pm
Neutron stars, often called “dead” stars, are amazing objects. Their study in recent decades has become one of the most fascinating and discovery-rich areas of astrophysics. Interest in neutron stars is due not only to the mystery of their structure, but also to their colossal density and strong magnetic and gravitational fields. The matter there is in special condition, resembling a huge atomic nucleus, and these conditions cannot be reproduced in earthly laboratories.
Birth at the tip of a pen
The discovery of a new elementary particle, the neutron, in 1932 forced astrophysicists to wonder what role it might play in the evolution of stars. Two years later, it was suggested that supernova explosions are associated with the transformation of ordinary stars into neutron stars. Then calculations were made of the structure and parameters of the latter, and it became clear that if small stars (like our Sun) at the end of their evolution turn into white dwarfs, then heavier ones become neutron ones. In August 1967, radio astronomers, while studying the flickering of cosmic radio sources, discovered strange signals - very short, lasting about 50 milliseconds, pulses of radio emission were recorded, repeated at a strictly defined time interval (about one second). This was completely different from the usual chaotic picture of random irregular fluctuations in radio emission. After a thorough check of all the equipment, we were confident that the pulses had extraterrestrial origin. It is difficult for astronomers to be surprised by objects emitting with variable intensity, but in in this case the period was so short, and the signals were so regular, that scientists seriously suggested that they could be news from extraterrestrial civilizations.
Therefore, the first pulsar was named LGM-1 (from English Little Green Men - “Little Green Men”), although attempts to find any meaning in the received impulses ended in vain. Soon, 3 more pulsating radio sources were discovered. Their period again turned out to be much less than the characteristic times of vibration and rotation of all known astronomical objects. Due to the pulsed nature of the radiation, new objects began to be called pulsars. This discovery literally shook up astronomy, and reports of pulsar detections began to arrive from many radio observatories. After the discovery of a pulsar in the Crab Nebula, which arose due to a supernova explosion in 1054 (this star was visible during the day, as the Chinese, Arabs and North Americans mention in their annals), it became clear that pulsars are somehow related to supernova explosions .
Most likely, the signals came from an object left after the explosion. It took a long time before astrophysicists realized that pulsars were the rapidly rotating neutron stars they had been looking for for so long.
Although most neutron stars have been detected by radio emission, they emit the bulk of their energy in the gamma-ray and x-ray ranges. Neutron stars are born very hot, but cool quickly enough, and already at a thousand years of age they have a surface temperature of about 1,000,000 K. Therefore, only young neutron stars shine in the X-ray range due to purely thermal radiation.
Pulsar physics
A pulsar is simply a huge magnetized top spinning around an axis that does not coincide with the axis of the magnet. If nothing fell on it and it did not emit anything, then its radio emission would have a rotational frequency and we would never hear it on Earth. But the fact is that this top has a colossal mass and high temperature surface, and the rotating magnetic field creates an electric field of enormous intensity, capable of accelerating protons and electrons almost to the speed of light. Moreover, all these charged particles rushing around the pulsar are trapped in its colossal magnetic field. And only within a small solid angle around the magnetic axis they can break free (neutron stars have the strongest magnetic fields in the Universe, reaching 10 10 -10 14 gauss, for comparison: the earth's field is 1 gauss, the solar one - 10-50 gauss) . It is these streams of charged particles that are the source of the radio emission from which pulsars were discovered, which later turned out to be neutron stars. Since the magnetic axis of a neutron star does not necessarily coincide with the axis of its rotation, when the star rotates, a stream of radio waves propagates through space like a strobe beacon - only momentarily cutting through the surrounding darkness.
X-ray images of the Crab Nebula pulsar in its active (left) and normal (right) states
nearest neighbor
This pulsar is located only 450 light years from Earth and is a binary system of a neutron star and a white dwarf with an orbital period of 5.5 days. Soft x-ray radiation, received by the ROSAT satellite, emit polar caps PSR J0437-4715 heated to two million degrees. During its rapid rotation (the period of this pulsar is 5.75 milliseconds), it turns toward the Earth with one or the other magnetic pole, as a result, the intensity of the gamma ray flux changes by 33%. The bright object next to the small pulsar is a distant galaxy that, for some reason, actively glows in the X-ray region of the spectrum.
Almighty Gravity
According to modern theory evolution, massive stars end their lives with a colossal explosion, turning most of them into an expanding gas nebula. As a result, what remains from a giant many times larger than our Sun in size and mass is a dense hot object about 20 km in size, with a thin atmosphere (of hydrogen and heavier ions) and a gravitational field 100 billion times greater than that of the Earth. It was called a neutron star, believing that it consists mainly of neutrons. Neutron star matter is the densest form of matter (a teaspoon of such a supernucleus weighs about a billion tons). The very short period of signals emitted by pulsars was the first and most important argument in favor of the fact that these are neutron stars, possessing a huge magnetic field and rotating at breakneck speed. Only dense and compact objects (only a few tens of kilometers in size) with a powerful gravitational field can withstand such a rotation speed without falling into pieces due to centrifugal inertial forces.
Neutron star consists of a neutron liquid with an admixture of protons and electrons. "Nuclear liquid", very similar to the substance from atomic nuclei, 1014 times denser than ordinary water. This huge difference is understandable - after all, atoms consist mainly of empty space, in which light electrons flit around a tiny, heavy nucleus. The nucleus contains almost all the mass, since protons and neutrons are 2,000 times heavier than electrons. The extreme forces generated by the formation of a neutron star compress the atoms so much that the electrons squeezed into the nuclei combine with protons to form neutrons. In this way, a star is born, consisting almost entirely of neutrons. A super-dense nuclear liquid, if brought to Earth, would explode like nuclear bomb, but in a neutron star it is stable due to the enormous gravitational pressure. However, in the outer layers of a neutron star (as, indeed, of all stars), pressure and temperature drop, forming a solid crust about a kilometer thick. It is believed to consist mainly of iron nuclei.
Flash
The colossal X-ray flare of March 5, 1979, it turns out, occurred far beyond our Galaxy, in the Large Magellanic Cloud, a satellite of our Milky Way, located at a distance of 180 thousand light years from Earth. Joint processing of the gamma-ray burst on March 5, recorded by seven spacecraft, made it possible to quite accurately determine the position of this object, and the fact that it is located precisely in the Magellanic Cloud is today practically beyond doubt.
The event that happened on this distant star 180 thousand years ago is difficult to imagine, but it flashed then like 10 supernovae, more than 10 times the luminosity of all the stars in our Galaxy. Bright dot in the upper part of the figure is a long and well-known SGR pulsar, and the irregular outline is the most likely position of the object that flared up on March 5, 1979.
Origin of the neutron star
Flash supernova- this is simply the transition of part of the gravitational energy into thermal energy. When an old star runs out of fuel and thermonuclear reaction can no longer heat its depths to the required temperature, a collapse occurs—the collapse of the gas cloud onto its center of gravity. The energy released in this process scatters the outer layers of the star in all directions, forming an expanding nebula. If the star is small, like our Sun, then an outburst occurs and a white dwarf is formed. If the mass of the star is more than 10 times that of the Sun, then such a collapse leads to a supernova explosion and an ordinary neutron star is formed. If a supernova erupts in the place of a very large star, with a mass of 20-40 solar, and a neutron star with a mass of more than three solar is formed, then the process of gravitational compression becomes irreversible and a black hole is formed.
Internal structure
The solid crust of the outer layers of a neutron star consists of heavy atomic nuclei arranged in a cubic lattice, with electrons flying freely between them, which is reminiscent of terrestrial metals, but only much denser.
Open question
Although neutron stars have been intensively studied for about three decades, they internal structure unknown for certain. Moreover, there is no firm certainty that they really consist mainly of neutrons. As you move deeper into the star, pressure and density increase and matter can be so compressed that it breaks up into quarks - building blocks protons and neutrons. According to modern quantum chromodynamics, quarks cannot exist in a free state, but are combined into inseparable “threes” and “twos”. But perhaps at the border inner core At the neutron star, the situation changes and the quarks break out of their confinement. To further understand the nature of a neutron star and exotic quark matter, astronomers need to determine the relationship between the star's mass and its radius ( average density). By studying neutron stars with satellites, it is possible to measure their mass quite accurately, but determining their diameter is much more difficult. More recently, scientists using the XMM-Newton X-ray satellite have found a way to estimate the density of neutron stars based on gravitational redshift. Another unusual thing about neutron stars is that as the mass of the star decreases, its radius increases - as a result smallest size have the most massive neutron stars.
Black Widow
The explosion of a supernova quite often imparts considerable speed to a newborn pulsar. Such a flying star with a decent magnetic field of its own strongly disturbs the ionized gas filling interstellar space. A kind of shock wave is formed, running in front of the star and diverging into a wide cone after it. The combined optical (blue-green part) and X-ray (shades of red) image shows that here we are dealing not just with a luminous gas cloud, but with a huge flow elementary particles, emitted by this millisecond pulsar. The linear speed of the Black Widow is 1 million km/h, it rotates around its axis in 1.6 ms, it is already about a billion years old, and it has a companion star circling around the Widow with a period of 9.2 hours. The pulsar B1957+20 received its name for the simple reason that it powerful radiation it simply burns its neighbor, causing the gas that forms it to “boil” and evaporate. The red cigar-shaped cocoon behind the pulsar is the part of space where the electrons and protons emitted by the neutron star emit soft gamma rays.
Result computer modeling allows you to very clearly, in cross-section, imagine the processes occurring near a fast-flying pulsar. The rays diverging from a bright point are a conventional image of the flow of radiant energy, as well as the flow of particles and antiparticles that emanates from a neutron star. The red outline at the boundary of the black space around the neutron star and the red glowing clouds of plasma is the place where the stream of relativistic particles flying almost at the speed of light meets the dense shock wave interstellar gas. By braking sharply, the particles emit X-rays and, having lost most of their energy, no longer heat up the incident gas so much.
Cramp of the Giants
Pulsars are considered one of the early stages of the life of a neutron star. Thanks to their study, scientists learned about magnetic fields, and about the speed of rotation, and about future fate neutron stars. By constantly monitoring the behavior of a pulsar, one can determine exactly how much energy it loses, how much it slows down, and even when it will cease to exist, having slowed down so much that it cannot emit powerful radio waves. These studies confirmed many theoretical predictions about neutron stars.
Already by 1968, pulsars with a rotation period from 0.033 seconds to 2 seconds were discovered. The frequency of radio pulsar pulses is maintained with amazing accuracy, and at first the stability of these signals was higher than the earth's atomic clocks. And yet, with progress in the field of time measurement, it was possible to register regular changes in their periods for many pulsars. Of course, these are extremely small changes, and only over millions of years can we expect the period to double. The ratio of the current rotation speed to the rotation deceleration is one way to estimate the age of the pulsar. Despite the remarkable stability of the radio signal, some pulsars sometimes experience so-called "disturbances." In a very short time interval (less than 2 minutes), the rotation speed of the pulsar increases by a significant amount, and then after some time returns to the value that was before the “disturbance.” It is believed that the “disturbances” may be caused by a rearrangement of mass within the neutron star. But anyway precise mechanism unknown yet.
Thus, the Vela pulsar undergoes large “disturbances” approximately once every 3 years, and this makes it very interesting object to study such phenomena.
Magnetars
Some neutron stars, called soft-gamma-ray burst sources (SGRs), emit powerful bursts of “soft” gamma-rays at irregular intervals. The amount of energy emitted by an SGR in a typical flare lasting a few tenths of a second can be emitted by the Sun in only whole year. Four known SGRs are located within our Galaxy and only one is outside it. These incredible bursts of energy can be caused by starquakes—powerful versions of earthquakes that rupture the solid surface of neutron stars and release powerful streams of protons from their cores, which, stuck in a magnetic field, emit gamma and X-rays. Neutron stars were identified as sources of powerful gamma-ray bursts after the huge gamma-ray burst on March 5, 1979, released as much energy in the first second as the Sun emits in 1,000 years. Recent observations of one of the most active neutron stars currently appear to support the theory that irregular, powerful bursts of gamma and X-ray radiation are caused by starquakes.
In 1998, the famous SGR suddenly woke up from its “slumber,” which had shown no signs of activity for 20 years and splashed out almost as much energy as the gamma-ray flare of March 5, 1979. What struck the researchers most when observing this event was the sharp slowdown in the speed of rotation of the star, indicating its destruction. To explain powerful gamma-ray and X-ray flares, a model of a magnetar—a neutron star with a super-strong magnetic field—was proposed. If a neutron star is born, rotating very quickly, then the combined influence of rotation and convection, which plays important role in the first few seconds of a neutron star's existence, can create a huge magnetic field as a result complex process, known as an “active dynamo” (the same way a field is created inside the Earth and the Sun). Theorists were amazed to discover that such a dynamo, operating in a hot, newborn neutron star, could create a magnetic field 10,000 times stronger than the normal field of pulsars. When the star cools (after 10 or 20 seconds), convection and the action of the dynamo stop, but this time is enough for the necessary field to arise.
The magnetic field of a rotating electrically conducting ball can be unstable, and a sharp restructuring of its structure can be accompanied by the release of colossal amounts of energy (a clear example of such instability is the periodic transfer of the Earth’s magnetic poles). Similar things happen on the Sun, in explosive events called " solar flares" In a magnetar, the available magnetic energy is enormous, and this energy is quite enough to power such giant flares as March 5, 1979 and August 27, 1998. Such events inevitably cause deep disruption and changes in the structure of not only electrical currents in the volume of the neutron star, but also its solid crust. Another mysterious type of object that emits powerful X-ray radiation during periodic explosions are so-called anomalous X-ray pulsars - AXPs. They differ from ordinary X-ray pulsars in that they emit only in the X-ray range. Scientists believe that SGR and AXP are phases of the life of the same class of objects, namely magnetars, or neutron stars, which emit soft gamma rays by drawing energy from a magnetic field. And although magnetars today remain the brainchild of theorists and there is not enough data confirming their existence, astronomers are persistently searching for the necessary evidence.
Magnetar candidates
Astronomers have already thoroughly studied our home galaxy Milky Way, that it costs them nothing to depict its side view, indicating on it the position of the most remarkable of the neutron stars.
Scientists believe that AXP and SGR are simply two stages in the life of the same giant magnet - a neutron star. For the first 10,000 years, the magnetar is an SGR - a pulsar, visible in ordinary light and producing repeated bursts of soft X-ray radiation, and for the next millions of years it, already like an anomalous AXP pulsar, disappears from the visible range and puffs only in the X-ray.
The strongest magnet
Analysis of data obtained by the RXTE satellite (Rossi X-ray Timing Explorer, NASA) during observations of the unusual pulsar SGR 1806-20 showed that this source is the most powerful magnet known to date in the Universe. The magnitude of its field was determined not only on the basis of indirect data (from the slowing down of the pulsar), but also almost directly - from measuring the rotation frequency of protons in the magnetic field of the neutron star. The magnetic field near the surface of this magnetar reaches 10 15 gauss. If it were, for example, in the orbit of the Moon, all magnetic storage media on our Earth would be demagnetized. True, taking into account the fact that its mass is approximately equal to that of the Sun, this would no longer matter, since even if the Earth had not fallen on this neutron star, it would have been spinning around it like crazy, making a full revolution in just an hour.
Active dynamo
We all know that energy loves to change from one form to another. Electricity easily turns into heat, and kinetic energy into potential energy. Huge convective flows of electrically conductive magma, plasma or nuclear matter, it turns out, can also kinetic energy transform into something unusual, such as a magnetic field. Moving large masses on a rotating star in the presence of a small initial magnetic field can lead to electric currents, creating a field in the same direction as the original one. As a result, an avalanche-like increase in the own magnetic field of a rotating current-conducting object begins. The larger the field, the larger the currents, the larger the currents, the larger the field - and all this is due to banal convective flows, due to the fact that hot matter is lighter than cold matter, and therefore floats up...
Troubled neighborhood
The famous Chandra space observatory has discovered hundreds of objects (including in other galaxies), indicating that not all neutron stars are destined to lead a solitary life. Such objects are born in dual systems that survived the supernova explosion that created the neutron star. And sometimes it happens that single neutron stars in dense stellar regions such as globular clusters capture a companion. In this case, the neutron star will “steal” matter from its neighbor. And depending on how massive star will keep her company, this “theft” will cause different consequences. Gas flowing from a companion with a mass less than that of our Sun onto such a “crumb” as a neutron star cannot immediately fall due to its own angular momentum being too large, so it creates a so-called accretion disk around it from the “stolen » matter. Friction as it wraps around the neutron star and compression in the gravitational field heats the gas to millions of degrees, and it begins to emit X-rays. Other interesting phenomenon associated with neutron stars that have a low-mass companion - X-ray bursts (bursters). They usually last from several seconds to several minutes and at maximum give the star a luminosity almost 100 thousand times greater than the luminosity of the Sun.
These flares are explained by the fact that when hydrogen and helium are transferred to the neutron star from the companion, they form a dense layer. Gradually this layer becomes so dense and hot that a reaction begins thermonuclear fusion and a huge amount of energy is released. In terms of power, this is equivalent to the explosion of the entire nuclear arsenal of earthlings on every square centimeter surface of a neutron star for a minute. A completely different picture is observed if the neutron star has a massive companion. The giant star loses matter in the form of stellar wind (a stream of ionized gas emanating from its surface), and the enormous gravity of the neutron star captures some of this matter. But here the magnetic field comes into its own, causing the falling matter to flow along power lines to the magnetic poles.
This means that X-ray radiation is primarily generated in hot spots at the poles, and if the magnetic axis and the rotation axis of the star do not coincide, then the brightness of the star turns out to be variable - it is also a pulsar, but only an X-ray one. Neutron stars in X-ray pulsars have bright giant stars as companions. In bursters, the companions of neutron stars are faint, low-mass stars. The age of bright giants does not exceed several tens of millions of years, while the age of faint dwarf stars can be billions of years, since the former spend their energy much faster. nuclear fuel than the latter. It follows that bursters are old systems in which the magnetic field has weakened over time, while pulsars are relatively young, and therefore the magnetic fields in them are stronger. Perhaps bursters pulsated at some point in the past, but pulsars are yet to burst in the future.
Pulsars with the shortest periods (less than 30 milliseconds)—the so-called millisecond pulsars—are also associated with binary systems. Despite their rapid rotation, they turn out to be not the youngest, as one would expect, but the oldest.
They arise from binary systems where an old, slowly rotating neutron star begins to absorb matter from its also aged companion (usually a red giant). As matter falls onto the surface of a neutron star, it transfers rotational energy to it, causing it to spin faster and faster. This happens until the neutron star's companion, almost freed of excess mass, becomes a white dwarf, and the pulsar comes to life and begins to rotate at a speed of hundreds of revolutions per second. However, recently astronomers discovered very unusual system, where the companion of the millisecond pulsar is not a white dwarf, but a giant, bloated red star. Scientists believe that they are observing this binary system just at the stage of “liberation” of the red star from excess weight and becoming a white dwarf. If this hypothesis is incorrect, then the companion star could be an ordinary globular cluster star accidentally captured by a pulsar. Almost all neutron stars that are currently known are found either in X-ray binaries or as single pulsars.
And recently Hubble noticed in visible light a neutron star that is not a component of a binary system and does not pulsate in the X-ray or radio range. This gives unique opportunity accurately determine its size and make adjustments to ideas about the composition and structure of this bizarre class of burnt-out stars compressed by gravity. This star was first discovered as an X-ray source and emits in this range not because it collects hydrogen gas as it moves through space, but because it is still young. It may be the remnant of one of the stars in the binary system. As a result of a supernova explosion, this binary system collapsed and former neighbors began an independent journey through the Universe.
Little Star Eater
Just as stones fall to the ground, so big star, releasing its mass piece by piece, gradually moves to a small and distant neighbor, which has a huge gravitational field near its surface. If the stars didn't revolve around general center gravity, then the gas stream could simply flow, like a stream of water from a mug, onto a small neutron star. But since the stars swirl in a round dance, the falling matter, before it reaches the surface, must lose most its angular momentum. And here, the mutual friction of particles moving along different trajectories and the interaction of the ionized plasma forming the accretion disk with the magnetic field of the pulsar help the process of matter fall to successfully end with an impact on the surface of the neutron star in the region of its magnetic poles.
Riddle 4U2127 solved
This star has been fooling astronomers for more than 10 years, showing strange slow variability in its parameters and flaring up differently each time. Only latest research space observatory"Chandra" allowed to solve mysterious behavior this object. It turned out that these were not one, but two neutron stars. Moreover, both of them have companions - one star is similar to our Sun, the other is like a small blue neighbor. Spatially, these pairs of stars are separated enough long distance and live an independent life. But on stellar sphere they are projected almost to the same point, which is why they were considered one object for so long. These four stars are located in globular cluster M15 at a distance of 34 thousand light years.
Open question
In total, astronomers have discovered about 1,200 neutron stars to date. Of these, more than 1,000 are radio pulsars, and the rest are simply X-ray sources. Over the years of research, scientists have come to the conclusion that neutron stars are true originals. Some are very bright and calm, others periodically flare up and change with starquakes, and others exist in binary systems. These stars are among the most mysterious and elusive astronomical objects, combining the strongest gravitational and magnetic fields and extreme densities and energies. And every new discovery from their turbulent life gives scientists unique information necessary to understand the nature of Matter and the evolution of the Universe.
Universal standard
Send something outside solar system very difficult, therefore, together with the Pioneer-10 and -11 spacecraft heading there 40 years ago, the earthlings also sent messages to their brothers in mind. Drawing something that will be understandable to the Extraterrestrial Mind is not an easy task; moreover, it was also necessary to indicate the return address and the date of sending the letter... How clearly the artists were able to do all this is difficult for a person to understand, but the very idea of using radio pulsars for indicating the place and time of sending the message is brilliant. Intermittent rays of various lengths emanating from a point symbolizing the Sun indicate the direction and distance to the pulsars closest to the Earth, and the intermittency of the line is nothing more than a binary designation of their period of revolution. The longest beam points to the center of our Galaxy - the Milky Way. The frequency of the radio signal emitted by a hydrogen atom when the mutual orientation of the spins (direction of rotation) of the proton and electron changes is taken as the unit of time in the message.
The famous 21 cm or 1420 MHz should be known to all intelligent beings in the Universe. Using these landmarks, pointing to the “radio beacons” of the Universe, it will be possible to find earthlings even after many millions of years, and by comparing the recorded frequency of pulsars with the current one, it will be possible to estimate when these man and woman blessed the first flight spaceship, who left the solar system.
In astronomy, there are many stars whose brightness is constantly changing, sometimes increasing, sometimes decreasing. Available stars, they are called Cepheids (after the first of them, discovered in the constellation Cepheus), with strictly periodic variations in brightness. Increasing and weakening of brightness occurs at different stars of this class with periods ranging from several days to a year. But we have never met before pulsars stars with a period as short as that of the first “Cambridge” pulsar.
Following him in very a short time Several dozen pulsars have been discovered, and the periods of some of them were even shorter. Thus, the period of the pulsar discovered in 1968 in the center of the Crab Nebula was 0.033 s. About four hundred pulsars are now known. The vast majority of them- up to 90% - has periods ranging from 0.3 to 3 s, so that a typical period of pulsars can be considered a period of 1 s. But especially interesting are record-breaking pulsars, whose period is shorter than typical. The record of the Crab Nebula pulsar lasted almost a decade and a half. At the end of 1982, a pulsar with a period of 0.00155 s, i.e. 1.55 ms, was discovered in the constellation Chanterelle. Rotation with such an amazingly short period means 642 rps. The very short periods of pulsars provided the first and strongest argument for interpreting these objects as rotating neutron stars. A star rotating so quickly must be extremely dense. Indeed, its very existence is possible only on the condition that the centrifugal forces associated with rotation less strength gravity that binds matter stars. Centrifugal forces cannot break the star if the centrifugal acceleration at the equator Q2R is less than the gravitational acceleration GM/R2.
Here M, R are mass and radius stars, Q is the angular frequency of its rotation, G is the gravitational constant. From the inequality for accelerations follows the inequality for average density stars
Q 2 R
M/R 3 = p > Q 2 /G
If we take the period of the Crab Nebula pulsar P=0.033 s, then the corresponding rotation frequency Q=2p/P will be approximately 200 rad/s. On this basis, we find the lower limit of its density
P > 6*10 14 kg/m 3
This is a very significant density, millions of times. exceeds the density of white dwarfs of the densest stars observed so far. Estimating the density based on the period of a “millisecond” pulsar, P=0.00155 s, Q=4000 rad/s, leads to an even higher value:
P > 2*10 17 kg/m 3
This density approaches the density of matter inside atomic nuclei: = 10 18.
So compact, compressed to such high degree there can only be neutron stars: their density is really close to nuclear. This conclusion is confirmed by the entire fifteen-year history of studying pulsars. But what is the origin of the rapid rotation of pulsar neutron stars? It is undoubtedly caused by strong compression stars when it is transformed from "ordinary" stars to neutron. Stars always have rotation with one speed or another period: the Sun, for example, rotates around its axis with a period of about a month. When a star contracts, its rotation speeds up. The same thing happens to her as to an ice dancer: by pressing his hands towards himself, the dancer accelerates his rotation. One of the basic laws of mechanics applies here - the law of conservation of angular momentum (or angular momentum). It follows from it that when the size of a rotating body changes, the speed of its rotation also changes; but the product MQR2 remains unchanged (which is, up to an insignificant numerical factor, the angular momentum). In this product, Q is the rotation frequency of the body, M is its mass, R is the size of the body in the direction, perpendicular to the axis rotation, which in the case of a spherical stars matches. with its radius. With a constant mass, the product remains constant, and, therefore, with a decrease in the size of the body, the frequency of its rotation increases according to the QR 2 law: QR -2.
A neutron star is formed by the compression of the central region, the core stars, which has exhausted its nuclear fuel reserves. The R=10 7 nucleus still manages to shrink to the size of a white dwarf.
Further compression to neutron size stars, means a decrease in radius by a thousand times. R=10 4 m.
Accordingly, the rotation frequency should increase by a million times and its period should decrease by the same amount. Instead of, say, a month, the star now makes one revolution around its axis in just three seconds. A faster initial rotation gives even shorter periods. Nowadays not only pulsars emitting in the radio range are known - they are called radio pulsars, but also X-ray pulsars emitting regular pulses x-rays. They also turned out to be neutron stars; There is a lot in their physics that makes them similar to bursters. But both radio pulsars and X-ray pulsars differ from bursters in one fundamental respect: they have very strong magnetic fields. It is magnetic fields - together with rapid rotation - that create the pulsation effect, although these fields act differently in radio pulsars and X-ray pulsars.
Neutron stars, often called “dead” stars, are amazing objects. Their study in recent decades has become one of the most fascinating and discovery-rich areas of astrophysics. Interest in neutron stars is due not only to the mystery of their structure, but also to their colossal density and strong magnetic and gravitational fields. The matter there is in a special state, reminiscent of a huge atomic nucleus, and these conditions cannot be reproduced in earthly laboratories.
Birth at the tip of a pen
The discovery of a new elementary particle, the neutron, in 1932 led astrophysicists to wonder what role it might play in the evolution of stars. Two years later, it was suggested that supernova explosions are associated with the transformation of ordinary stars into neutron stars. Then calculations were made of the structure and parameters of the latter, and it became clear that if small stars (like our Sun) at the end of their evolution turn into white dwarfs, then heavier ones become neutron ones. In August 1967, radio astronomers, while studying the flickering of cosmic radio sources, discovered strange signals: very short, lasting about 50 milliseconds, pulses of radio emission were recorded, repeated at a strictly defined time interval (of the order of one second). This was completely different from the usual chaotic picture of random irregular fluctuations in radio emission. After a thorough check of all the equipment, we became confident that the pulses were of extraterrestrial origin. It is difficult for astronomers to be surprised by objects emitting with variable intensity, but in this case the period was so short and the signals were so regular that scientists seriously suggested that they could be news from extraterrestrial civilizations.
Therefore, the first pulsar was named LGM-1 (from the English Little Green Men “Little Green Men”), although attempts to find any meaning in the received pulses ended in vain. Soon, 3 more pulsating radio sources were discovered. Their period again turned out to be much less than the characteristic times of vibration and rotation of all known astronomical objects. Due to the pulsed nature of the radiation, new objects began to be called pulsars. This discovery literally shook up astronomy, and reports of pulsar detections began to arrive from many radio observatories. After the discovery of a pulsar in the Crab Nebula, which arose due to a supernova explosion in 1054 (this star was visible during the day, as the Chinese, Arabs and North Americans mention in their annals), it became clear that pulsars are somehow related to supernova explosions .
Most likely, the signals came from an object left after the explosion. It took a long time before astrophysicists realized that pulsars were the rapidly rotating neutron stars they had been looking for for so long.
Crab Nebula
The outbreak of this supernova (photo above), sparkling in the earth's sky brighter than Venus and visible even during the day, occurred in 1054 according to earth clocks. Almost 1,000 years is a very short period of time by cosmic standards, and yet during this time the beautiful Crab Nebula managed to form from the remains of the exploding star. This image is a composition of two pictures: one of them was obtained by the Hubble Space Optical Telescope (shades of red), the other X-ray telescope"Chandra" (blue). It is clearly seen that high-energy electrons emitting in the X-ray range very quickly lose their energy, therefore blue colors prevail only in the central part of the nebula.
Combining two images helps to more accurately understand the mechanism of operation of this amazing cosmic generator emitting electromagnetic vibrations the widest frequency range from gamma rays to radio waves. Although most neutron stars have been detected by radio emission, they emit the bulk of their energy in the gamma-ray and x-ray ranges. Neutron stars are born very hot, but cool quickly enough, and already at a thousand years of age they have a surface temperature of about 1,000,000 K. Therefore, only young neutron stars shine in the X-ray range due to purely thermal radiation.
Pulsar physics
A pulsar is simply a huge magnetized top spinning around an axis that does not coincide with the axis of the magnet. If nothing fell on it and it did not emit anything, then its radio emission would have a rotational frequency and we would never hear it on Earth. But the fact is that this top has a colossal mass and a high surface temperature, and the rotating magnetic field creates a huge electric field, capable of accelerating protons and electrons almost to the speed of light. Moreover, all these charged particles rushing around the pulsar are trapped in its colossal magnetic field. And only within a small solid angle about the magnetic axis they can break free (neutron stars have the strongest magnetic fields in the Universe, reaching 10 10 10 14 gauss, for comparison: the earth’s field is 1 gauss, the solar one 10 50 gauss) . It is these streams of charged particles that are the source of the radio emission from which pulsars were discovered, which later turned out to be neutron stars. Since the magnetic axis of a neutron star does not necessarily coincide with the axis of its rotation, when the star rotates, a stream of radio waves propagates through space like the beam of a flashing beacon, only momentarily cutting through the surrounding darkness.
X-ray images of the Crab Nebula pulsar in its active (left) and normal (right) states
nearest neighbor
This pulsar is located only 450 light years from Earth and is a binary system of a neutron star and a white dwarf with an orbital period of 5.5 days. The soft X-ray radiation received by the ROSAT satellite is emitted by the polar ice caps PSR J0437-4715, which are heated to two million degrees. During its rapid rotation (the period of this pulsar is 5.75 milliseconds), it turns toward the Earth with one or the other magnetic pole, as a result, the intensity of the gamma ray flux changes by 33%. The bright object next to the small pulsar is a distant galaxy that, for some reason, actively glows in the X-ray region of the spectrum.
Almighty Gravity
According to modern evolutionary theory, massive stars end their lives in a colossal explosion, turning most of them into an expanding nebula of gas. As a result, what remains from a giant many times larger than our Sun in size and mass is a dense hot object about 20 km in size, with a thin atmosphere (of hydrogen and heavier ions) and a gravitational field 100 billion times greater than that of the Earth. It was called a neutron star, believing that it consists mainly of neutrons. Neutron star matter is the densest form of matter (a teaspoon of such a supernucleus weighs about a billion tons). The very short period of signals emitted by pulsars was the first and most important argument in favor of the fact that these are neutron stars, possessing a huge magnetic field and rotating at breakneck speed. Only dense and compact objects (only a few tens of kilometers in size) with a powerful gravitational field can withstand such a rotation speed without falling into pieces due to centrifugal inertial forces.
A neutron star consists of a neutron liquid mixed with protons and electrons. The “nuclear liquid,” which closely resembles the substance of atomic nuclei, is 1014 times denser than ordinary water. This huge difference is understandable, since atoms consist mostly of empty space, in which light electrons flit around a tiny, heavy nucleus. The nucleus contains almost all the mass, since protons and neutrons are 2,000 times heavier than electrons. The extreme forces generated by the formation of a neutron star compress the atoms so much that the electrons squeezed into the nuclei combine with protons to form neutrons. In this way, a star is born, consisting almost entirely of neutrons. The super-dense nuclear liquid, if brought to Earth, would explode like a nuclear bomb, but in a neutron star it is stable due to the enormous gravitational pressure. However, in the outer layers of a neutron star (as, indeed, of all stars), pressure and temperature drop, forming a solid crust about a kilometer thick. It is believed to consist mainly of iron nuclei.
Flash
The colossal X-ray flare of March 5, 1979, it turns out, occurred far beyond our Galaxy, in the Large Magellanic Cloud, a satellite of our Milky Way, located at a distance of 180 thousand light years from Earth. Joint processing of the gamma-ray burst on March 5, recorded by seven spacecraft, made it possible to quite accurately determine the position of this object, and the fact that it is located precisely in the Magellanic Cloud is today practically beyond doubt.
The event that happened on this distant star 180 thousand years ago is difficult to imagine, but it flashed then like 10 supernovae, more than 10 times the luminosity of all the stars in our Galaxy. The bright dot at the top of the figure is a long-known and well-known SGR pulsar, and the irregular outline is the most likely position of the object that flared up on March 5, 1979.
Origin of the neutron star
A supernova explosion is simply the transition of part of the gravitational energy into heat. When an old star runs out of fuel and the thermonuclear reaction can no longer heat its interior to the required temperature, a collapse of the gas cloud occurs at its center of gravity. The energy released in this process scatters the outer layers of the star in all directions, forming an expanding nebula. If the star is small, like our Sun, then an outburst occurs and a white dwarf is formed. If the mass of the star is more than 10 times that of the Sun, then such a collapse leads to a supernova explosion and an ordinary neutron star is formed. If a supernova erupts in the place of a very large star, with a mass of 20 x 40 solar, and a neutron star with a mass of more than three solar is formed, then the process of gravitational compression becomes irreversible and a black hole is formed.
Internal structure
The solid crust of the outer layers of a neutron star consists of heavy atomic nuclei arranged in a cubic lattice, with electrons flying freely between them, which is reminiscent of terrestrial metals, but only much denser.
Open question
Although neutron stars have been intensively studied for about three decades, their internal structure is not known for certain. Moreover, there is no firm certainty that they really consist mainly of neutrons. As you move deeper into the star, pressure and density increase and matter can be so compressed that it breaks down into quarks - the building blocks of protons and neutrons. According to modern quantum chromodynamics, quarks cannot exist in a free state, but are combined into inseparable “threes” and “twos”. But perhaps, at the boundary of the inner core of a neutron star, the situation changes and the quarks break out of their confinement. To further understand the nature of a neutron star and exotic quark matter, astronomers need to determine the relationship between the star's mass and its radius (average density). By studying neutron stars with satellites, it is possible to measure their mass quite accurately, but determining their diameter is much more difficult. More recently, scientists using the XMM-Newton X-ray satellite have found a way to estimate the density of neutron stars based on gravitational redshift. Another unusual thing about neutron stars is that as the mass of the star decreases, its radius increases; as a result, the most massive neutron stars have the smallest size.
Black Widow
The explosion of a supernova quite often imparts considerable speed to a newborn pulsar. Such a flying star with a decent magnetic field of its own greatly disturbs the ionized gas filling interstellar space. A kind of shock wave is formed, running in front of the star and diverging into a wide cone after it. The combined optical (blue-green part) and X-ray (shades of red) image shows that here we are dealing not just with a luminous gas cloud, but with a huge stream of elementary particles emitted by this millisecond pulsar. The linear speed of the Black Widow is 1 million km/h, it rotates around its axis in 1.6 ms, it is already about a billion years old, and it has a companion star circling around the Widow with a period of 9.2 hours. The pulsar B1957+20 received its name for the simple reason that its powerful radiation simply burns its neighbor, causing the gas that forms it to “boil” and evaporate. The red cigar-shaped cocoon behind the pulsar is the part of space where the electrons and protons emitted by the neutron star emit soft gamma rays.
The result of computer modeling makes it possible to very clearly, in cross-section, present the processes occurring near a fast-flying pulsar. The rays diverging from a bright point are a conventional image of the flow of radiant energy, as well as the flow of particles and antiparticles that emanates from a neutron star. The red outline at the border of the black space around the neutron star and the red glowing clouds of plasma is the place where the stream of relativistic particles flying almost at the speed of light meets the interstellar gas compacted by the shock wave. By braking sharply, the particles emit X-rays and, having lost most of their energy, no longer heat up the incident gas so much.
Cramp of the Giants
Pulsars are considered one of the early stages of the life of a neutron star. Thanks to their study, scientists learned about magnetic fields, the speed of rotation, and the further fate of neutron stars. By constantly monitoring the behavior of a pulsar, one can determine exactly how much energy it loses, how much it slows down, and even when it will cease to exist, having slowed down so much that it cannot emit powerful radio waves. These studies confirmed many theoretical predictions about neutron stars.
Already by 1968, pulsars with a rotation period from 0.033 seconds to 2 seconds were discovered. The periodicity of the radio pulsar pulses is maintained with amazing accuracy, and at first the stability of these signals was higher than the earth's atomic clocks. And yet, with progress in the field of time measurement, it was possible to register regular changes in their periods for many pulsars. Of course, these are extremely small changes, and only over millions of years can we expect the period to double. The ratio of the current rotation speed to the rotation deceleration is one of the ways to estimate the age of the pulsar. Despite the remarkable stability of the radio signal, some pulsars sometimes experience so-called "disturbances." In a very short time interval (less than 2 minutes), the rotation speed of the pulsar increases by a significant amount, and then after some time returns to the value that was before the “disturbance.” It is believed that the “disturbances” may be caused by a rearrangement of mass within the neutron star. But in any case, the exact mechanism is still unknown.
Thus, the Vela pulsar undergoes large “disturbances” approximately every 3 years, and this makes it a very interesting object for studying such phenomena.
Magnetars
Some neutron stars, called repeating soft gamma ray burst sources (SGRs), emit powerful bursts of "soft" gamma rays at irregular intervals. The amount of energy emitted by an SGR in a typical flare lasting a few tenths of a second can only be emitted by the Sun in a whole year. Four known SGRs are located within our Galaxy and only one is outside it. These incredible explosions of energy can be caused by starquakes - powerful versions of earthquakes when the solid surface of neutron stars is torn apart and powerful streams of protons burst from their depths, which, stuck in a magnetic field, emit gamma and X-ray radiation. Neutron stars were identified as sources of powerful gamma-ray bursts after the huge gamma-ray burst on March 5, 1979, released as much energy in the first second as the Sun emits in 1,000 years. Recent observations of one of the most active neutron stars currently appear to support the theory that irregular, powerful bursts of gamma and X-ray radiation are caused by starquakes.
In 1998, the famous SGR suddenly woke up from its “slumber,” which had shown no signs of activity for 20 years and splashed out almost as much energy as the gamma-ray flare of March 5, 1979. What struck the researchers most when observing this event was the sharp slowdown in the speed of rotation of the star, indicating its destruction. To explain powerful gamma-ray and X-ray flares, a magnetar-neutron star model with a superstrong magnetic field was proposed. If a neutron star is born spinning very quickly, then the combined influence of rotation and convection, which plays an important role in the first few seconds of the neutron star's life, can create a huge magnetic field through a complex process known as an "active dynamo" (the same way the field is created inside the Earth and the Sun). Theorists were amazed to discover that such a dynamo, operating in a hot, newborn neutron star, could create a magnetic field 10,000 times stronger than the normal field of pulsars. When the star cools (after 10 or 20 seconds), convection and the action of the dynamo stop, but this time is enough for the necessary field to arise.
The magnetic field of a rotating electrically conducting ball can be unstable, and a sharp restructuring of its structure can be accompanied by the release of colossal amounts of energy (a clear example of such instability is the periodic transfer of the Earth’s magnetic poles). Similar things happen on the Sun, in explosive events called "solar flares." In a magnetar, the available magnetic energy is enormous, and this energy is quite enough to power such giant flares as March 5, 1979 and August 27, 1998. Such events inevitably cause deep disruption and changes in the structure of not only electrical currents in the volume of the neutron star, but also its solid crust. Another mysterious type of object that emits powerful X-ray radiation during periodic explosions is the so-called anomalous X-ray pulsarsAXP. They differ from ordinary X-ray pulsars in that they emit only in the X-ray range. Scientists believe that SGR and AXP are phases of the life of the same class of objects, namely magnetars, or neutron stars, which emit soft gamma rays by drawing energy from a magnetic field. And although magnetars today remain the brainchild of theorists and there is not enough data confirming their existence, astronomers are persistently searching for the necessary evidence.
Magnetar candidates
Astronomers have already studied our home galaxy, the Milky Way, so thoroughly that it costs them nothing to depict its side view, indicating the position of the most remarkable of the neutron stars.
Scientists believe that AXP and SGR are simply two stages in the life of the same giant magnet neutron star. For the first 10,000 years, the magnetar is an SGR pulsar, visible in ordinary light and producing repeated bursts of soft X-ray radiation, and for the next millions of years it, like an anomalous AXP pulsar, disappears from the visible range and puffs only in the X-ray.
The strongest magnet
Analysis of data obtained by the RXTE satellite (Rossi X-ray Timing Explorer, NASA) during observations of the unusual pulsar SGR 1806-20 showed that this source is the most powerful magnet known to date in the Universe. The magnitude of its field was determined not only on the basis of indirect data (from the slowing down of the pulsar), but also almost directly from measuring the rotation frequency of protons in the magnetic field of the neutron star. The magnetic field near the surface of this magnetar reaches 10 15 gauss. If it were, for example, in the orbit of the Moon, all magnetic storage media on our Earth would be demagnetized. True, taking into account the fact that its mass is approximately equal to that of the Sun, this would no longer matter, since even if the Earth had not fallen on this neutron star, it would have been spinning around it like crazy, making a full revolution in just an hour.
Active dynamo
We all know that energy loves to change from one form to another. Electricity easily turns into heat, and kinetic energy into potential energy. Huge convective flows of electrically conductive magma, plasma or nuclear matter, it turns out, can also convert their kinetic energy into something unusual, for example, into a magnetic field. The movement of large masses on a rotating star in the presence of a small initial magnetic field can lead to electric currents that create a field in the same direction as the original one. As a result, an avalanche-like increase in the own magnetic field of a rotating current-conducting object begins. The greater the field, the greater the currents, the greater the currents, the greater the field and all this is due to banal convective flows, due to the fact that a hot substance is lighter than a cold one, and therefore floats up
Troubled neighborhood
The famous Chandra space observatory has discovered hundreds of objects (including in other galaxies), indicating that not all neutron stars are destined to lead a solitary life. Such objects are born in binary systems that survived the supernova explosion that created the neutron star. And sometimes it happens that single neutron stars in dense stellar regions such as globular clusters capture a companion. In this case, the neutron star will “steal” matter from its neighbor. And depending on how massive the star is to accompany it, this “theft” will cause different consequences. Gas flowing from a companion with a mass less than that of our Sun onto such a “crumb” as a neutron star cannot immediately fall due to its own angular momentum being too large, so it creates a so-called accretion disk around it from the “stolen » matter. Friction as it wraps around the neutron star and compression in the gravitational field heats the gas to millions of degrees, and it begins to emit X-rays. Another interesting phenomenon associated with neutron stars that have a low-mass companion is X-ray bursts. They usually last from several seconds to several minutes and at maximum give the star a luminosity almost 100 thousand times greater than the luminosity of the Sun.
These flares are explained by the fact that when hydrogen and helium are transferred to the neutron star from the companion, they form a dense layer. Gradually, this layer becomes so dense and hot that a thermonuclear fusion reaction begins and a huge amount of energy is released. In terms of power, this is equivalent to the explosion of the entire nuclear arsenal of earthlings on every square centimeter of the surface of a neutron star within a minute. A completely different picture is observed if the neutron star has a massive companion. The giant star loses matter in the form of stellar wind (a stream of ionized gas emanating from its surface), and the enormous gravity of the neutron star captures some of this matter. But here the magnetic field comes into its own, causing the falling matter to flow along the lines of force towards the magnetic poles.
This means that X-ray radiation is primarily generated at hot spots at the poles, and if the magnetic axis and the rotation axis of the star do not coincide, then the brightness of the star turns out to be variable - it is also a pulsar, but only an X-ray one. Neutron stars in X-ray pulsars have bright giant stars as companions. In bursters, the companions of neutron stars are faint, low-mass stars. The age of bright giants does not exceed several tens of millions of years, while the age of faint dwarf stars can be billions of years old, since the former consume their nuclear fuel much faster than the latter. It follows that bursters are old systems in which the magnetic field has weakened over time, and pulsars are relatively young, and therefore the magnetic fields in them are stronger. Perhaps bursters pulsated at some point in the past, but pulsars are yet to burst in the future.
Pulsars with the shortest periods (less than 30 milliseconds)—the so-called millisecond pulsars—are also associated with binary systems. Despite their rapid rotation, they turn out to be not the youngest, as one would expect, but the oldest.
They arise from binary systems where an old, slowly rotating neutron star begins to absorb matter from its also aged companion (usually a red giant). As matter falls onto the surface of a neutron star, it transfers rotational energy to it, causing it to spin faster and faster. This happens until the neutron star's companion, almost freed of excess mass, becomes a white dwarf, and the pulsar comes to life and begins to rotate at a speed of hundreds of revolutions per second. However, recently astronomers discovered a very unusual system, where the companion of a millisecond pulsar is not a white dwarf, but a giant bloated red star. Scientists believe that they are observing this binary system just at the stage of “liberating” the red star from excess weight and turning into a white dwarf. If this hypothesis is incorrect, then the companion star could be an ordinary globular cluster star accidentally captured by a pulsar. Almost all neutron stars that are currently known are found either in X-ray binaries or as single pulsars.
And recently, Hubble noticed in visible light a neutron star, which is not a component of a binary system and does not pulsate in the X-ray and radio range. This provides a unique opportunity to accurately determine its size and make adjustments to ideas about the composition and structure of this bizarre class of burnt-out, gravitationally compressed stars. This star was first discovered as an X-ray source and emits in this range not because it collects hydrogen gas as it moves through space, but because it is still young. It may be the remnant of one of the stars in the binary system. As a result of a supernova explosion, this binary system collapsed and the former neighbors began an independent journey through the Universe.
Baby star eater
Just as stones fall to the ground, so a large star, releasing bits of its mass, gradually moves to a small and distant neighbor, which has a huge gravitational field near its surface. If the stars did not revolve around a common center of gravity, then the gas stream could simply flow, like a stream of water from a mug, onto a small neutron star. But since the stars swirl in a circle, the falling matter must lose most of its angular momentum before it reaches the surface. And here, the mutual friction of particles moving along different trajectories and the interaction of the ionized plasma forming the accretion disk with the magnetic field of the pulsar help the process of matter fall to successfully end with an impact on the surface of the neutron star in the region of its magnetic poles.
Riddle 4U2127 solved
This star has been fooling astronomers for more than 10 years, showing strange slow variability in its parameters and flaring up differently each time. Only the latest research from the Chandra space observatory has made it possible to unravel the mysterious behavior of this object. It turned out that these were not one, but two neutron stars. Moreover, both of them have companions: one star is similar to our Sun, the other is like a small blue neighbor. Spatially, these pairs of stars are separated by a fairly large distance and live an independent life. But on the stellar sphere they are projected to almost the same point, which is why they were considered one object for so long. These four stars are located in the globular cluster M15 at a distance of 34 thousand light years.
Open question
In total, astronomers have discovered about 1,200 neutron stars to date. Of these, more than 1,000 are radio pulsars, and the rest are simply X-ray sources. Over the years of research, scientists have come to the conclusion that neutron stars are real originals. Some are very bright and calm, others periodically flare up and change with starquakes, and others exist in binary systems. These stars are among the most mysterious and elusive astronomical objects, combining the strongest gravitational and magnetic fields and extreme densities and energies. And every new discovery from their turbulent life gives scientists unique information necessary to understand the nature of Matter and the evolution of the Universe.
Universal standard
It is very difficult to send something outside the solar system, so together with the Pioneer 10 and 11 spacecraft that headed there 30 years ago, earthlings also sent messages to their brothers in mind. To draw something that would be understandable to the Extraterrestrial Mind is not an easy task; moreover, it was also necessary to indicate the return address and the date of sending the letter... How clearly the artists were able to do all this is difficult for a person to understand, but the very idea of using radio pulsars for indicating the place and time of sending the message is brilliant. Intermittent rays of various lengths emanating from a point symbolizing the Sun indicate the direction and distance to the pulsars closest to the Earth, and the intermittency of the line is nothing more than a binary designation of their period of revolution. The longest beam points to the center of our Galaxy Milky Way. The frequency of the radio signal emitted by a hydrogen atom when the mutual orientation of the spins (direction of rotation) of the proton and electron changes is taken as the unit of time in the message.
The famous 21 cm or 1420 MHz should be known to all intelligent beings in the Universe. Using these landmarks, pointing to the “radio beacons” of the Universe, it will be possible to find earthlings even after many millions of years, and by comparing the recorded frequency of pulsars with the current one, it will be possible to estimate when these man and woman blessed the flight of the first spaceship that left the solar system.
Nikolay Andreev
Predicted by theorists, in particular, academician L. A. Landau in 1932.
Transformations of stars
Stars don't last forever. Depending on what the star was and how its existence proceeded, the star will turn or in white dwarf, or in neutron star.
If a star collapses, it forms black hole in space.
These are the ideas about the “death” of stars, developed by academician Ya. B. Zeldovich and his students. White dwarfs have been known for a very long time.
For three decades, there was controversy surrounding this prediction. Disputes, but not searches. It was pointless to search for neutron stars using ground-based observatories: they probably do not emit visible rays, and rays from other parts of the electromagnetic spectrum are powerless to overcome the armor shield of the earth's atmosphere.
Universe from outer space
The search began only when the opportunity arose to look at Universe from outer space.
At the end of 1967, astronomers made a sensational discovery. At a certain point in the sky it suddenly lit up and went out after hundredths of a second. radio point source. About a second later the flash repeated. These repetitions followed each other with the precision of a ship's chronometer. It seemed as if a distant lighthouse was winking at the observers through the black night of the Universe.
Then quite a lot of such lighthouses became known. It turned out that they are different from each other periodicity of beam pulses, radiation composition. Majority pulsars- as these newly discovered stars were called - had a total period duration of from a quarter of a second to four seconds.
Today, the number of pulsars known to science is about 2000. And the possibilities for new discoveries are far from exhausted.
Pulsars are neutron stars. It is difficult to imagine any other mechanism that ignites and extinguishes a pulsar flare with iron precision than the rotation of the star itself. A radiation source is “installed” on one side of the star, and with each revolution around its axis, the emitted beam momentarily falls on our Earth.
But what stars are capable of rotating at a speed of several revolutions per second? Neutron - and no others.
Ours, for example, makes one revolution in almost 25 days; increase the speed - and the centrifugal forces will simply tear it apart, blow it to pieces.
However, on neutron stars , the substance is compressed to a density unimaginable in normal conditions. Every cubic centimeter The substance of a neutron star under terrestrial conditions would weigh from 100 thousand to 10 billion tons!
The fatal contraction sharply reduces the diameter of the star. If in their shining life stars have diameters of hundreds of thousands and millions of kilometers, then the radii of neutron stars are rarely
exceed 20-30 kilometers. Such a small “flywheel”, and, moreover, firmly riveted by the forces of universal gravity, can be spun at a speed of several revolutions per second - it will not fall apart.
A neutron star must rotate very quickly. Have you seen how a ballerina spins, rising on one toe and pressing her arms tightly to her body? But when she spread her arms, her rotation immediately slowed down.
The physicist will say: the moment of inertia has increased. As its radius decreases, the moment of inertia of a neutron star, on the contrary, decreases; it seems to “press its arms” closer and closer to its body. The speed of its rotation quickly increases. And when the diameter of the star decreases to the value indicated above, the number of its revolutions around its axis should be exactly the same as that provided by the “pulsar effect”.
Physicists would really like to be on the surface of a neutron star and conduct some experiments. After all, conditions must exist there, the likes of which are not found anywhere else: a fantastic magnitude gravitational field and fantastic magnetic field strength.
According to scientists' calculations, if the contracting star had a magnetic field of a very modest magnitude - one oersted (the Earth's magnetic field, obediently turning the blue compass needle to the north, is equal to approximately half an oersted), then the field strength of a neutron star can reach 100 million and trillion oersteds !
In the 20s of the twentieth century, during his work in the laboratory of E. Rutherford, the famous Soviet physicist academician P. L. Kapitsa Conducted experience in obtaining super-strong magnetic fields. He managed to obtain a magnetic field of unprecedented intensity in a volume of two cubic centimeters - up to 320 thousand oersteds. Of course, this record has now been surpassed.
By using the most complex tricks, bringing down an entire electric Niagara - a power of a million kilowatts - onto a single turn of the solenoid and exploding an auxiliary powder charge, they manage to obtain a magnetic field strength of up to 25 million oersteds.
This field exists for several millionths of a second. And on a neutron star a constant field thousands of times larger is possible!
Structure of a neutron star
Soviet scientist academician V. L. Ginzburg painted a pretty detailed picture neutron star structure. Its surface layers should be in a solid state, and already at a depth of a kilometer, with increasing temperature, the solid crust should be replaced by a neutron liquid containing in its composition a certain admixture of protons and electrons, a liquid with amazing properties, superfluid and superconducting.
The structure of the neutron star pulsar In terrestrial conditions the only example superfluid is the behavior of so-called helium-2, liquid helium, at temperatures close to absolute zero. Helium-2 can instantly flow out of a vessel through tiny hole, is able, ignoring the force of gravity, to rise up the wall of the test tube.
Superconductivity is also known under terrestrial conditions only at very low temperatures. Like superfluidity, it is a manifestation in our conditions of the laws of the world of elementary particles.
In the very center of a neutron star, according to Academician V.L. Ginzburg, there may be a non-superfluid and non-superconducting core.
Two giant fields - gravitational and magnetic - create a kind of crown around the neutron star. The axis of rotation of the star does not coincide with the magnetic axis, this causes the “pulsar effect”.
If you imagine that magnetic pole Earth, (more details:) is located on the site of Lake Baikal and that a radio transmitter antenna is installed at this place, aimed at the zenith, with a fairly narrow beam, then any area of space falling within the “visibility” zone of this beam will periodically receive transmitter signals.
Thus, a neutron star pulsar emits narrowly directed streams of radio emission, which, as a result of the rotation of the neutron star, fall into the field of view of the observer at regular intervals.