Unique Neutron Star Discovered

This year is rich in discoveries of unusualspace objects. So, recently we wrote that astronomers discovered a planet that should not exist. Now, with the help of the Green Bank Telescope, scientists have found the most massive neutron star in the entire history of observations. Neutron stars are rather strange - they are almost entirely composed of neutrons and have incredible density. The mass of the discovered star, which was not given the most beautiful name J0740 + 6620, is 2.17 times greater than the mass of the Sun, and its diameter is 30 kilometers. The study will be published in the journal Nature Astronomy.

It is believed that neutron stars collapse into black holes

What are neutron stars?

Agree, the Universe is a strange thing. It contains galactic filaments, superclusters of galaxies, dark matter, Fermi bubbles, black holes, neutron stars ... the list goes on and on. And if we told you about the cosmic web quite recently, today we suggest paying attention to neutron stars.

To begin with, that denser objects inUniverse except neutron stars are only black holes. Researchers rightly believe that the study of neutron stars can bring them closer to understanding the extreme physics of the universe - in the end, it is these stars that collapse into space monsters. In fact, a neutron star is a massive atomic nucleus that has very strange properties. So, J0740 + 6620 is the densest and strangest neutron star in the entire history of observations.

Neutron stars are one of the most mysterious objects in the universe.

Because stars, like you and me, are aging anddie, their final state depends on the mass. To understand how neutron stars are formed from dying stars, you first need to understand how white dwarfs are formed. The fact is that 97% of the stars in the Universe are white dwarfs. They consist of electron-nuclear plasma and are devoid of sources of thermonuclear energy. Moreover, they are the next most dense type of stars after neutron due to a kind of “built-in” cosmic stop sign. Simply put, white dwarfs are so dense that the atomic bonds of their material are broken. This turns them into a plasma of atomic nuclei and electrons. At the same time, gaining a higher density than white dwarfs is quite difficult - the electrons do not want to be in the same state with each other and will resist compression to a certain point where this can happen. Physicists call this the degeneration of electrons.

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Stars whose mass does not exceed 10 solar masses,tend to become white dwarfs. The mass limit of white dwarfs is about 1.44 solar masses. But a denser star with a mass of 10 to 29 solar masses can become a neutron star. The fact is that at this moment the star density is so high that it overcomes the degeneracy of electrons: the electrons still do not want to occupy the same state, therefore they are forced to combine with protons, as a result of which neutrons are formed and neutrinos are emitted. Thus, neutron stars are almost entirely composed of neutrons and are retained due to their degeneration, which is similar to the degeneracy of electrons in white dwarfs.

Schematic illustration of a pulsar J074 + 6620. The sphere in the middle represents a neutron star, the curves show the lines of the magnetic field, and the protruding cones show the radiation zones.

At the same time, research co-author Scott Ransomnotes that neutron stars have a tipping point when their internal density becomes so extreme that gravity inhibits the ability of neutrons to withstand further collapse. Thus, if the mass of J074 + 6620 were larger, then the star would simply collapse into a black hole. Each "most massive" neutron star that scientists discover gradually brings experts closer to identifying the very turning point that keeps the neutron star from collapsing.

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How do astronomers look for neutron stars?

In the Milky Way, there are at least 100million neutron stars, but most of them are ancient, cold stars, so they are very difficult to detect. Fortunately, J0740 + 6620 is a pulsar. Recall that pulsars are the type of rapidly rotating neutron stars that emit radio waves and other electromagnetic radiation. When the pulsar rotates, these rays "pulsate" with enviable regularity, which is somewhat reminiscent of the clock. Most neutron stars are difficult to identify, but when the pulsar's radio waves penetrate the Earth, it becomes much easier to detect and study.

The collision of two neutron stars

Pulsar J0740 + 6620 lives in a binary system according tonext door to the white dwarf. When a white dwarf passed in front of a beam of neutron star radio waves, astronomers on our planet were able to detect a slight delay in the incoming radio waves. This happened because the gravity of the white dwarf curved the space around it, causing the passing radio waves to travel one touch farther than usual. By measuring this, astronomers were able to calculate the mass of the white dwarf. And knowing the mass of one object in a binary system, you can easily calculate the mass of another. Thus, the researchers found that J0740 + 6620 is the most massive neutron star to date.

Study authors hope their workIt will help scientists in such fields of science as high-energy physics, relativistic astrophysics, etc. And all because, in addition to the properties of neutron stars listed in the article, when these objects merge, the heaviest elements in the Universe are formed.