The objects that will be discussed in the article were discovered by chance, although the scientists Landau L.D. and Oppenheimer R. predicted their existence back in 1930. We are talking about neutron stars. About the characteristics and features of these cosmic bodies and will be discussed in the article.
Neutron and the same name star
After predicting the existence of neutron stars in the 30s of the 20th century and after the neutron was discovered (1932), Baade V. together with Zwick F. in 1933 at the congress of physicists in America announced the possibility of forming an object called neutron star. This is a cosmic body that occurs during the explosion of supernovae.
However, all calculations were only theoretical, since it was not possible to prove such a theory in practice due to the lack of appropriate astronomical equipment and the too small size of a neutron star. But in 1960, X-ray astronomy began to develop. Then, quite unexpectedly, neutron stars were discovered due to radio surveillance.
Opening
The year 1967 was significant in this area. Bell D., being a graduate student of Huish E., was able to discover a cosmic object - a neutron star. This is a body emitting a constant radiation of radio wave pulses. The phenomenon was compared with a space beacon because of the narrow direction of the radio beam, which came from a very fast rotating object. The fact is that any other standard star would not be able to maintain its integrity at such a high rotational speed. Only neutron stars are capable of this, among which the pulsar PSR B1919 + 21 became the first open.
The fate of massive stars is very different from small ones. In such luminaries there comes a moment when the gas pressure no longer balances the gravitational forces. Such processes lead to the fact that the star begins to contract unlimitedly (collapse). With a star mass exceeding the solar one by 1.5-2 times, collapse will be inevitable. During compression, the gas inside the stellar core heats up. At first, everything happens very slowly.
Collapse
Reaching a certain temperature, the proton is able to turn into neutrinos, which immediately leave the star, taking with them energy. The collapse will intensify until all protons are converted into neutrinos. Thus, a pulsar, or neutron star, is formed. This is a collapsing core.
The outer shell during the formation of the pulsar receives compression energy, which after will be at a speed of not one thousand km / s. thrown into space. In this case, a shock wave is formed, which can lead to a new star formation. In such a star, the luminosity is billions of times higher than the original. After such a process, for a period of time from one week to a month, the star emits light in an amount exceeding the whole galaxy. Such a celestial body is called a supernova. Its explosion leads to the formation of a nebula. At the center of the nebula is a pulsar, or neutron star. This is the so-called descendant of a star that exploded.
Visualization
In the depths of the entire space of space, amazing events take place, among them - the collision of stars. Thanks to a complex mathematical model, NASA scientists were able to visualize the riot of a huge amount of energy and the degeneration of the matter involved in this. An incredibly powerful picture of a cosmic cataclysm is played before the eyes of observers. The probability that a collision of neutron stars will occur is very high. The meeting of two such luminaries in space begins with their entanglement in gravitational fields. Possessing a huge mass, they, so to speak, exchange hugs. In a collision, a severe explosion occurs, accompanied by an incredibly powerful emission of gamma radiation.
If we consider a neutron star separately, then these are the remnants after a supernova explosion, in which the life cycle ends. The mass of the surviving star exceeds the solar by 8-30 times. The universe is often illuminated by supernova explosions. The probability that neutron bodies will meet in the universe is quite high.
A meeting
Interestingly, when two stars meet, the development of events cannot be foreseen unambiguously. One option describes the mathematical model proposed by NASA scientists from the Space Flight Center. The process begins with the fact that two neutron stars are located from each other in outer space at a distance of approximately equal to 18 km. By cosmic standards, neutron stars with a mass of 1.5-1.7 times more than the sun are considered tiny objects. Their diameter varies within 20 km. Due to such a mismatch between volume and mass, a neutron star is the owner of the strongest gravitational and magnetic fields. Just imagine: a teaspoon of neutron matter matter weighs like the whole Mount Everest!
Degeneration
The incredibly high gravitational waves of a neutron star, acting around it, are the reason that matter cannot be in the form of separate atoms that begin to collapse. Matter itself passes into a degenerate neutron, in which the structure of the neutrons themselves will not make it possible for the star to go into a singularity and then into a black hole. If the mass of degenerate matter begins to increase due to addition to it, then gravitational forces will be able to overcome the resistance of neutrons. Then nothing will prevent the destruction of the structure formed as a result of the collision of neutron stellar objects.
Mathematical model
Studying these celestial objects, scientists came to the conclusion that the density of a neutron star is comparable to the density of matter in the nucleus of an atom. Its indicators are in the range from 1015 kg / m³ to 1018 kg / m³. Thus, the independent existence of electrons and protons is impossible. The substance of a star practically consists of neutrons alone.
The created mathematical model demonstrates how powerful periodic gravitational interactions that occur between two neutron stars break through the thin shell of two stars and throw out a huge amount of radiation (energy and matter) into the space surrounding them. The process of rapprochement is very fast, literally in a split second. As a result of the collision, a toroidal ring of matter forms with a newborn black hole in the center.
Importance
Modeling such events is important. Thanks to them, scientists were able to understand how a neutron star and a black hole are formed, what happens when luminaries collide, how supernovae and many other processes of outer space arise and die. All these events are the source of the appearance of the heaviest chemical elements in the Universe, even heavier than iron, unable to form in any other way. This indicates the very importance of neutron stars in the entire universe.
The rotation of a celestial object of huge volume around its axis is amazing. Such a process causes a collapse, but with all this, the mass of a neutron star practically remains the same. If you imagine that the star will continue to shrink, then, according to the law of conservation of the moment of rotation, the angular velocity of rotation of the star will increase to incredible values. If a star needed about 10 days to complete a revolution, then as a result it would do the same revolution in 10 milliseconds! These are incredible processes!
Collapse development
Scientists are researching such processes. Perhaps we will witness new discoveries that so far seem fantastic to us! But what can be if we imagine the development of collapse further? To make it easier to imagine, we take for comparison a pair of neutron star / earth and their gravitational radii. So, with continuous compression, a star can reach a state where neutrons begin to turn into hyperons. The radius of the celestial body will become so small that in front of us will be a lump of a superplanetary body with a mass and a gravitational field of a star. This can be compared to the fact that if the earth became equal in size to the ping-pong ball, and the gravitational radius of our star, the Sun, would be equal to 1 km.
If you imagine that a small lump of stellar matter possesses the attraction of a huge star, then it is able to keep an entire planetary system near it. But the density of such a celestial body is too high. Through it, the rays of light gradually cease to break through, the body as if goes out, it ceases to be visible to the eye. Only the gravitational field does not change, which warns that there is a gravitational hole.
Discoveries and Observations
For the first time, gravitational waves from the fusion of neutron stars were recorded very recently: August 17. Two years ago, black holes merged. This is such an important event in astrophysics that 70 space observatories simultaneously conducted observations. Scientists were able to verify the correctness of the hypotheses about gamma-ray bursts; they succeeded in observing the synthesis of heavy elements described earlier by theorists.
Such widespread observation of gamma-ray burst, gravitational waves and visible light made it possible to determine the area in the sky in which a significant event occurred, and the galaxy where these stars were. This is NGC 4993.
Of course, astronomers have long observed short bursts of gamma radiation. But so far they have not been able to say exactly about their origin. Behind the main theory was a version of the fusion of neutron stars. Now she confirmed.
To describe a neutron star using a mathematical apparatus, scientists turn to the equation of state that relates density to the pressure of a substance. However, there are many such options, and scientists simply do not know which of the existing ones will be correct. It is hoped that gravitational observations will help resolve this issue. At the moment, the signal did not give a definite answer, but it already helps to evaluate the shape of the star, depending on the gravitational attraction to the second star (star).