The international team is developing a new method to determine the origin of stardust in the meteorite.
Analysis of meteorite content has been essential in advancing our knowledge of the origin and evolution of our solar system. Some meteorites also contain stardust grains. These grains precede the formation of our solar system and are now providing important insights into how the elements in the universe were formed.
Working in collaboration with an international team, nuclear physicists at the U.S. Department of Energy (DOE) Argonne National Laboratory have made a major breakthrough in analyzing the “presolar grains” found in some meteorites. This discovery has shed light on the nature of stellar explosions and the origin of chemical elements. It has also provided a new method for astronomical research.
“Small presolar grains, about one micron in size, are remnants of stellar explosions in the distant past, long before our solar system existed,” said Dariusz Seweryniak, an experimental nuclear physicist in the Argonne Physics department. Stellar debris from the explosions eventually became wed with meteorites that crashed to Earth.
“On the other hand, we were able to calculate the ratios of different sulfur isotopes produced in stellar explosions, which will allow astrophysicists to determine whether a particular presolar grain is of new origin or supernova.” – Dariusz Seweryniak, experimental physicist in the Physics sector
The main stellar explosions are of two types. One called “nova” includes a binary star system, where a prime star is orbiting a white dwarf star, an extremely dense star that may be the size of the Earth but that has the mass of our sun. The mat from the main star is constantly being pulled by the white dwarf because of its strong gravitational field. This deposited material initiates a thermonuclear explosion each 1000 in 100,000 years, and the white dwarf derives the mass equivalent of more than thirty Earths in interstellar space. In a “supernova”, a single collapsing star explodes and ejects most of its mass.
Nova and supernovae are the sources of the most frequent and violent stellar explosions in our Galaxy, and for this reason, they have been the subject of major astronomical investigations for decades. Many of them are accustomed, for example, to the origin of the heavier elements.
“A new way to study these phenomena is by analyzing the chemical and isotopic composition of presolary grains in the meteorite,” Seweryniak explained. “Of particular importance to our research is a specific nuclear reaction that occurs in nova and supernova – the capture of protons in a chlorine isotope – which we can only study indirectly in the laboratory.”
In conducting their research, the pioneering team took a new approach to astrophysics research. This includes the use of the Gamma-Ray Array (GRETINA) energy beam coupled with Fragment Mass Analyzer in the Argonne Tandem Linac Accelerator System (ATLAS), a DOE of Science Facility User for nuclear physics. GRETINA is an excellent detection system capable of tracking the path of gamma rays emitted by nuclear reactions. It is one of only two such systems in the world.
Using GRETINA, the team completed the first detailed gamma-ray spectroscopy study of an astronomically important nucleus of an isotope, argon-34. From the data, they calculated the rate of nuclear reaction involving the capture of protons in a chlorine isotope (chlorine –33).
“On the other hand, we were able to calculate the ratios of different sulfur isotopes produced in stellar explosions, which will allow astrophysicists to determine whether a particular presolar grain is of new origin or supernova,” he said. Seweryniak. The team also applied their acquired data to better understand the synthesis of elements in stellar explosions.
The team is planning to continue their research with GRETINA, as part of a worldwide effort to achieve a comprehensive understanding of the nucleosynthesis of elements in stellar explosions.
Reference: “Search for Nova Presolary Grains: γ-ray Spectroscopy 34Gold and Its Importance for Astrophysics 33Cl (p, γ) reaction ”by ARL Kennington, G. Lotay, DT Doherty, D. Seweryniak, C. Andreoiu, K. Auranen, MP Carpenter, WN Catford, CM Deibel, K. Hadyńska-Klęk, S. Hallam, DEM Hoff, T. Huang, RVF Janssens, S. Jazrawi, J. José, FG Kondev, T. Lauritsen, J. Li, AM Rogers, J. Saiz, G. Savard, S. Stolze, GL Wilson and S. Zhu , 26 June 2020, Physical Review Letters.
DOI: 10.1103 / PhysRevLett.124.252702
In addition to Seweryniak, authors include ARL Kennington, G. Lotay, DT Doherty, C. Andreoiu, K. Auranen, MP Carpenter, WN Catford, CM Deibel, K. Hadynska-Klek, S. Hallam, D. Hoff, T. Huang, RVF Janssens, S. Jazrawi, J. José, FG Kondev, T. Lauritsen, J. Li, AM Rogers, J. Saiz, G. Savard, S. Stolze, GL Wilson, and S. Zhu. Participating research institutions include the University of Surrey (UK), York University (UK), Simon Fraser University (Canada), Louisiana State University (USA), University of North Carolina (USA), Duke University (US), Universitat Politècnica de Catalunya (Spain), and Institut d’Estudis Espacials de Catalunya (Spain)).
This research was supported by the DOE Office of Science.