Gold is one of the most sought-after metals in the world, but its formation from heavy metals such as gold, thorium and uranium requires energetic conditions such as stellar explosions or collisions between neutron stars. This means that all heavy elements on Earth form under extreme conditions in the astrophysical environment.
Today, astrophysicists have an incomplete understanding of how elements heavier than iron are made. Researchers are intrigued by the question of whether these astrophysical phenomena have the right conditions for the formation of heavy elements. surprised, A new study This shows that these elements can form in the accretion disks of black holes.
The accretion disk is called rotating chaos, which swallows dust and gas from the space surrounding the active newborn black hole. In these extreme environments, the high rate of neutrino emission should facilitate the conversion of protons into neutrons, which is necessary for the process of forming heavier elements than the latter.
“In our study, we systematically investigated the neutron and proton exchange rates for a large number of disk configurations using detailed computer simulations for the first time, and found that disks are very rich in neutrons as long as certain conditions are met.” Explain Dr. Oliver Just, from the Relativistic Astrophysics Group at GSI’s Theory Research Division.
It just says It: The determining factor is the total mass of the disc. “Neutrons are formed from protons by electron capture under the supermassive disc, neutrino emission, and are available for heavy element synthesis through the r-process.”
Conversely, if the mass of the disk is very high, the reverse reaction plays a more important role, so that neutrinos are recaptured to a large extent by neutrinos before they leave the disk. These neutrinos are converted back into protons, making the fast neutron capture process, or R-process, difficult.
The study indicates that the optimal mass of the disk to become a factory of gold and other heavy materials is between 0.01 and 0.1 solar masses. As it is not currently clear how often these accretion discs occur in collapse systems, the research is not yet complete.
“These data are currently insufficient. But with next-generation accelerators such as the Facility for Antiproton and Ion Research (FAIR), we will be able to measure them with unprecedented precision in the future.” said Astrophysicist Andreas Paswein of the GSI Helmholtz Center for Heavy Ion Research.
A large number of elements are known to form inside stars, but when we move to elements heavier than iron, truly catastrophic events are used. One of the most extreme events occurs during the birth of black holes. However, astrophysicists are not convinced that the conditions actually exist, except for their relative contributions to the overall abundance of heavy elements in the universe.
The team is hard at work, using simulations to determine if this is true. Rhetorically we might call it the magical moment when astrophysics and computing came together to trace the history of objects common to us today, but as we have seen, its origins go back to cosmic phenomena, including strange black holes.
Published in Research Monthly Notices of the Royal Astronomical Society.
Share science, share knowledge.
