An international study with the participation of the University of Bonn also provides new insights into Hoyle’s puzzling situation. What is inside the nucleus of a carbon atom? A new study (The simulation provides an image of the carbon core) from the Forschungszentrum Jülich, Michigan State University (USA) and the University of Bonn provides the first comprehensive answer to this question. In the study, the researchers identified all the energy levels of the space. These include the puzzling Hoyle situation.
Without it, carbon and oxygen would be in the atmosphere only in small amounts. So, ultimately, we owe our existence to him. The study has now been published in the journal “Nature Communications”.
The nucleus of a carbon atom usually contains six protons and six neutrons. But how exactly are they organized? And how does their structure change when the nucleus is bombarded with high-energy radiation? For decades, science has been searching for answers to these questions.
Not least because they can provide the main mystery and long puzzled physicists: why there is a significant amount of carbon in the universe – atoms without which there would be no life on earth ?
After all, shortly after the Big Bang, there was only hydrogen and helium. The nucleus of hydrogen contains one proton, that of helium two protons and two neutrons. All the heavier matter wasn’t formed until billions of years later from an aging star. In them, helium nuclei fuse into carbon atoms at high pressures and high temperatures.
It requires three helium nuclei to fuse together. “But this is really unlikely to happen,” says Professor Ulf Meißner from the Helmholtz Institute for Radiation and Nuclear Physics at the University of Bonn and the Institute for Advanced Simulation at the Forschungszentrum Jülich. Reason: Helium nuclei have higher energy than carbon nucleus.
However, this does not mean that they come together especially easily – on the contrary: it seems as if three people want to jump for joy. But since they run faster than the happy colors, they don’t.
Simulation on supercomputers
Around 1950, British astronomer Fred Hoyle postulated that three nuclei of the first helium had fused to form a variable. This “Hoyle state” can be similar to helium nuclei. To be in the game: this is a very fast carousel, which the three passengers can quickly jump on. When this happens, the carousel slows down.
“Only by traveling through the Hoyle state can stars produce carbon in any meaningful amount,” says Meißner, who is also a member of the trans disciplinary research area “Modeling” and “Matter” at the Bonn University Institute .
About ten years ago, together with American colleagues, Forschungszentrum Jülich and Ruhr-Universität Bochum, he succeeded for the first time in creating this Hoyle state. He explains, “We already have an idea of how the protons and neutrons of the carbon nucleus are organized in this state.”
“However, we have not yet been able to prove conclusively that this theory is true.” With the help of advanced techniques, researchers have succeeded now.
This depends on the catch: in fact, protons and neutrons – nucleons – can be anywhere in the universe. However, for their calculations, the team limited this freedom: “We arranged our nuclear particles at the edges of a three-dimensional network,” says Meißner. “So we only gave them some very specific conditions.”
Computation time: 5 million processor hours
Because of this restriction, it is possible to calculate the motion of nucleons. Since nuclear particles affect each other in different ways depending on their distance to each other, this task is complicated. The researchers then ran their simulations millions of times with slightly different starting conditions.
This allowed them to see where protons and neutrons might be. “We performed these calculations for all known energy states of carbon dioxide,” Meißner said.
The calculations were performed on the JEWELS supercomputer of the Forschungszentrum Jülich. They require a total of about five million CPU hours, with thousands of CPUs running concurrently.
The results provide a clear image of the carbon core. They show that nuclear particles do not exist independently. “Instead, they are grouped in groups of two neutrons and two protons each,” explains the scientist.
This means that the three helium nuclei can still be detected as they combine to form carbon atoms. Depending on the power situation, they are in different types of space – either arranged in an isosceles triangle or like a slightly broken arm, and the shoulder, knee joint and wrist each have one.
Not only that the study allows researchers to understand the physics of the carbon core. Meißner: “The methods we have developed can be easily used to make other spaces that lead to really new insights.
Source: University of Bonn
