A rare type of supernova is able to explain the mystery of astrophysics 40-year-old

Most of antimatter, filling the space of our galaxy the Milky Way, may be the remnants of dead stars, a new study. According to the scientists, their work is able to solve the puzzle in astrophysics, existing for more than 40 years.

A rare type of supernova is able to explain the mystery of astrophysics 40-year-old

Each particle of ordinary matter has antipode - antimatter have the same mass, but it has the opposite charge. For example, the antiparticle of the negatively charged electron is the positively charged positron. When the particles and antiparticle face, this results in their destruction (annihilation) and powerful ejection energy. Just one gram of antimatter, faced with one gram of normal matter, is capable of causing an explosion, in which the energy level of emissions will be twice higher than in the explosion of the bomb dropped on Hiroshima.

More than 40 years ago, scientists first determined that the gamma rays emitted in the annihilation of positrons, are produced at this point in all directions of the galaxy. On the basis of this discovery was made an assumption that every second inside the Milky Way there is the annihilation of positrons 10 ^ 43 (unit with 43 zeros). The same study indicated that the presence of the majority of these positrons was determined in the galactic center (central bridge), but not in the galactic disk, despite the fact that most bridge contains less than half the mass of the Milky Way. Was made the assumption that the source of emission of positrons is radioactive material, is synthesized by stars. However, over the next few decades, scientists have been unable to determine the type of star that can generate an amount of antimatter. It was later made another assumption: emission of positrons can create occasional sources such as supermassive black holes in galactic centers the majority, as well as dark matter particles annihilate each other.

"The source of these positrons - the puzzle with more than 40-year history. But positrons to explain you do not need the presence of any exotic elements such as dark matter, "- commented the lead author of a new study, an astrophysicist at the Australian National University Roland Crocker.

In his opinion, this may be the source of a supernova - the catastrophic explosions of stars that can generate a huge amount of positrons. This, according to scientists, supported by the fact, which often detects these positrons.

Crocker drew their attention to a supernova similar object, known as SN 1991bg. A similar type of object, as it turns out, is more common in other galaxies, but it is much less than normal supernovae. Unlike most ordinary supernovae that could overshadow almost all other stars in the galaxy, to understand the kind of study supernovas produces a large amount of visible light and is considered very rare. And that is why, in the opinion of the investigator, so infrequently detected in the Milky Way. In previous studies it handed down the opinion that this type of dim supernovae can occur at the confluence of two white dwarfs. The latter have very high density and are dead star nucleus (the size of the Earth), remaining after the star fully developed its thermonuclear fuel and lost their outer layers. Most stars, including our sun, will one day become white dwarfs.

Returning to `type SN 1991bg, it should be noted that they appear particularly when a collision occurs between two white dwarfs have low mass, with one of them rich in carbon stocks and oxygen, and another - with helium. Despite its rarity among supernovae, this species is able to generate huge amounts of the radioactive isotope, known as Ti-44. And it was he who allocates those positrons, which were discovered by astronomers around the Milky Way.

At the time when most supernovae are born from young and massive stars, objects, like SN 1991bg, most often found in areas where prevail over the old stars aged from 3 to 6 billion years. This age difference might explain why previously discovered positrons observed mainly it is in the central bridge of the Milky Way, which contains a large number of older stars than in the outer galactic disk. Crocker says here that the cause of a certain amount of positrons may be other sources.

"Although it is not necessary, given that SN1991bg type objects can independently explain the whole phenomenology of positrons. Recent data indicate that the source of positrons tightly connected with the center of the galaxy. In our model, this is due to the fact that the old stars mainly scattered in a radius of 200 parsecs (650 light years) around the galactic center in the form of a supermassive black hole. Nevertheless, consider the black hole itself as an additional source would be very interesting, "- sums up Crocker.