Heavy items like gold, platinum anduranium can form in collapsing - rapidly rotating massive stars that collapse into black holes when their outer layers explode into a rare supernova. The disk of the material revolving around the new black hole for its power, can create the conditions necessary for astronomical alchemy, according to a press release of a new study by scientists from Columbia University, published by Science News. The full version of the report is accepted for publication by the journal Nature.
“Black holes born in such extreme conditions are still picky eaters,” said astrophysicist Brian Metzger of Columbia University, co-author of the study.
Computer simulations carried out by scientistsshows that for “one sitting” they are ways to “eat” a certain amount of matter, and what they “disdain” is carried by a cosmic wind rich in neutrons. This environment has suitable conditions for creating heavy elements, the researchers note.
Science has long puzzled over how appearthe heaviest elements in the universe. Lighter, such as carbon, oxygen and iron, are formed inside the stars, and then erupt in stellar explosions - supernovae. But to create the elements located below in the periodic table, an extreme medium densely filled with neutrons is required. In this environment, a chain of reactions may occur, known as the r-process, in which atomic nuclei quickly absorb neutrons and undergo radioactive decay to form new elements.
Previously, scientists assumed that in a collisionTwo dead stars (neutron) r-process can occur in a material blown up by fusion. This assumption was confirmed when astronomers first witnessed the collision of two neutron stars, which gave rise to a pulsation of space-time, also known as gravitational waves, and light. This cosmic firework showed signs of the formation of a mixture of heavy elements, including gold, silver and platinum.
However, an explanation involving neutronstars have some gaps. The fusion of these dead stars can take a long time. At the same time, scientists have discovered the presence of heavy elements in ancient stars, which were formed at the dawn of the history of the Universe. It is not yet clear whether the fusion of these astronomical objects could have occurred quickly enough to explain the presence of elements in these early stars.
Collapsars in turn can occur muchfaster, almost at the stage of formation of stars. And this phenomenon can be an effective producer of heavy elements, the Metzger group believes. As Metzger himself notes, one collapsar is capable of generating 30 times more r-process material than the merging of neutron stars. The researchers report that the collapse pairs may be responsible for 80 percent of the elements of the r-process in the Universe, and the merging of neutron stars for the rest.
The findings of the new research scientists allowtake a fresh look at the discovery of 2016, when astronomers discovered that a dwarf galaxy called Reticulum II experienced a cataclysm at the beginning of the history of the Universe, which left elements of the r-process in its stars. Then it was assumed that it was the fusion of ancient neutron stars that became the source of heavy elements in the Universe. The results of the latest study suggest a new candidate for the role of this source - collapsars.
Astrophysicist Anna Fröbel from the Massachusetts Institute of Technology, one of the co-authors of the 2016 study, agrees with the findings of the Metzger study.
“This is very exciting. Mergers of neutron stars are rare, so it seemed to me that we won the lottery. But collapsars are about 10 times less, therefore, if they explain it, it seems that we won the lottery twice, ”the scientist comments.
Scientists still do not know how oftencollapsars and whether they are able to produce the amount of material that could explain the abundance of heavy elements that is observed in our Universe.
“I think it’s still too early to make a verdict,” says astrophysicist Alexander G of the Observatory at the Carnegie Institute in Pasadena (California, USA), the second co-author of the 2016 study.
Now scientists want to understand collapsing orneutron stars better explain the behavior of galaxies like Reticulum II and the formation of heavy elements. Further observations of the effects of supernovae caused by collapses will also help to more accurately determine their role in this matter.
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