2023-12-11 09:45:24
How heavy can a chemical element be? Scientists have discovered that some stars were capable of producing chemical elements with mass numbers much higher than 260, or heavier than any element in the periodic table naturally present on Earth. The study further demonstrates that nuclear fission, not just fusion, creates chemical elements in the cosmos.
The mass number of a chemical element is the number of protons and neutrons in its nucleus.
The study is the work of the team of Ian U. Roederer, from the University of Michigan in Ann Arbor and now at North Carolina State University, and Matthew Mumpower, from the Los Alamos National Laboratory, in the United States, all of these entities.
Chemical elements beyond iron on the periodic table are thought to be created in cataclysmic explosions such as the merger between two neutron stars or in supernova explosions of an unusual kind. However, new research suggests that nuclear fission may play a major role in creating such very heavy elements.
By combining data on various chemical elements that were present in very old stars, researchers have found a potential signature of nuclear fission. The presence of this signature indicates that it is very likely that superheavy atomic nuclei are generated naturally, beyond the heaviest elements in the periodic table.
The merger of two neutron stars is one of the main candidate phenomena for producing the heaviest elements of the periodic table through the r process. The image shows the collision between two neutron stars. (Image: Los Alamos National Laboratory / Matthew Mumpower)
It was already suspected that nuclear fission occurred naturally and quite often in the cosmos, but until now no one had been able to prove it.
The team took a new look at the amounts of heavy elements in 42 well-studied stars in the Milky Way. It was already known that these stars harbor heavy elements formed in previous generations of stars. By analyzing the amounts of each heavy element present in these stars collectively, rather than individually as is more common, they identified previously unrecognized patterns.
These patterns indicate that some chemical elements that occur near the middle of the periodic table, such as silver and rhodium, are probably the result of nuclear fission of very heavy and completely unstable chemical elements. Such elements, including some from beyond the periodic table, were formed and an instant later their fleeting life ended in nuclear fission that produced distinct atomic nuclei.
The team has determined that through the phenomenon known as the “r process”, atoms with a mass number of well over 260 can be produced in stars before they fission.
No chemical element, natural or artificial, with such an atomic weight has ever been detected on Earth, not even in atomic explosions triggered during nuclear weapons tests.
The study is titled “Element abundance patterns in stars indicate fission of nuclei heavier than uranium.” And it has been published in the academic journal Science. (Source: NCYT from Amazings)
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