High-energy photons produced deep within gamma-ray burst jets emerge from decayed stars can dissolve the outer stellar layer into free neutrons, causing a series of physical processes that lead to the formation of heavy elements. paper It is published on Astrophysical Journal.
The high-energy photonic jet (white and blue) passes through a collapse with a black hole at its center. The red space around the jet represents a coco where free neutrons can be captured and caused the R process. Image credit: Los Alamos National Laboratory.
The formation of the heaviest elements relies on astrophysical environments with large amounts of neutrons.
Neutrons are found in the medium under extreme pressure, either bound to the nucleus.
Free neutrons are rare because they have a half-life of less than 15 minutes.
“The creation of heavy elements such as uranium and plutonium requires extreme conditions,” says Dr. Matthew Mumpoir, a physicist at the Los Alamos National Laboratory.
“There are several viable yet rare scenarios in the universe where these elements can form, and all such locations require a large number of neutrons. We propose a new phenomenon where these neutrons are not present and dynamically generated by stars.”
The key to generating the heaviest elements in the periodic table is known as the rapid neutron capture process or R process, and is believed to be responsible for the production of all thorium, uranium and plutonium that occur naturally in the universe.
The team’s framework takes on the challenging physics of the R process and solves them by proposing reactions and processes around the collapse of the stars.
In addition to understanding the formation of heavy elements, the proposed framework will help address key issues regarding neutron transport, multi-objective simulations, and observation of rare events. All of these are interesting for national security applications, which can gather insights from research.
In the scenario proposed by researchers, when nuclear fuel is exhausted, a large star begins to die.
It is no longer able to push its own gravity up, and a black hole forms in the center of the star.
If the black hole is spinning fast enough, the framedrazing effect from the very powerful gravity near the black hole will wind up the magnetic field and fire a powerful jet.
Subsequent reactions create a wide range of photons, some of which are high-energy.
“The jet blows stars before it, creating a hot coco of material around the jet, like a freight train plowing through the snow,” said Dr. Mumpower.
At the interface of jets with star materials, high-energy photons (i.e. light) can interact with the nucleus and convert protons into neutrons.
Existing nuclei can also be dissolved in individual nuclei, creating more free neutrons to power the R process.
Team calculations suggest that interactions with light can create neutrons very quickly in nanosecond order.
For charging, a strong magnetic field traps the protons in the jet.
The merciless neutrons are ploughed from the jet to the coco.
After experiencing relativistic shock, neutrons are very dense compared to the surrounding star material, which can lead to the R process, forging heavy elements and isotopes, and banished into space when the stars are torn apart.
The process of protons converted into neutrons and the free neutrons that escape to the surrounding coco to form heavy elements, encompasses all four basic forces of nature, accompanied by a wide range of physics principles. It combines the real multiword problems, the fields of nuclear and nuclear physics, with fluid mechanics and general relationships.
Despite the team’s efforts, more challenges remain as the heavy isotopes created during the R process have never been done on Earth.
Researchers know little about their properties, including atomic weights, half-life, and more.
The high energy jet framework proposed by the team may help explain the origin of kilonovas (the glow of optical and infrared electromagnetic radiation) associated with long gamma-ray bursts.
“Star melting via high-energy photon jets provides an alternative origin for gravity and the production of kilonova that can be produced. This may not have previously been thought to be related to star collapse,” the scientist said.
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Matthew R. Mumpoir et al. 2025. Make sure there are neutrons! Hadronic optical production from large fluxes of high energy photons. APJ 982, 81; doi:10.3847/1538-4357/ADB1E3
Source: www.sci.news
