Photo of GRETINA in ATLAS near Argonne. Credit: Argonne National Laboratory
International team develops a new method to determine the origin of stardust in meteorites.
Analysis of meteorite content has been crucial in furthering our knowledge of the origin and evolution of our solar system. Some meteorites also contain pellets of stardust. These grains predate the formation of our solar system and now provide important insights into how the elements formed in the universe.
Working in collaboration with an international team, nuclear physicists at the U.S. Department of Energy’s (DOEs) Argonne National Laboratory have made an important discovery in connection with the analysis of ‘presolar grains’ found in some meteorites. This discovery shed light on the nature of stellar explosions and the origin of chemical elements. It has also provided a new method for astronomical research.
“Tiny presolar grains, about one micron in size, are the remnant of stellar explosions in the distant past, long before our solar system existed,” said Dariusz Seweryniak, an experimental nuclear physicist in Argonne’s Physics division. The stellar pun of the explosions was eventually recovered in meteorites that collided in the Earth.
“We were able to determine the proportions of different sulfur isotopes produced in stellar explosions, allowing astrophysicists to determine whether a particular precolar nut is of nova or supernova origin.” – Dariusz Seweryniak, experimental physicist in the Department of Physics
The major stellar explosions are of two types. One called “nova” includes a binary galaxy, in which a main star is around a circle white dwarf star, an extremely dense star that may be the size of Earth, but has the mass of our Sun. Case of the main star is continuously removed by the white dwarf due to its intense gravitational field. This decomposed material each initiates a thermonuclear explosion 1,000 to 100,000 years, and the white dwarf brings out the equivalent of the mass of more than thirty Earths in interstellar space. In a “supernova” most mass explodes and explodes its single star.
Nova and supernova are the sources of the most frequent and violent stellar eruptions in our Galaxy, and for that reason they have been the subject of intense astronomical research for decades. Much has been learned from them, for example about the origin of the heavier elements.
“A new way to study these phenomena is to analyze the chemical and isotopic composition of the presolar grains in meteorites,” Seweryniak explained. “Of particular interest to our research is a specific nuclear reaction that occurs in nova and supernova – proton trap on an isotope of chlorine – that we can only study indirectly in the lab.”
In conducting their research, the team pioneered a new approach to astrophysical research. It includes use of the Gamma-Ray Energy Tracking In-beam Array (GRETINA) coupled to the Fragment Mass Analyzer at the Argonne Tandem Linac Accelerator System (ATLAS), a DOE Office of Science User Installation for Nuclear Physics. GRETINA is a state-of-the-art detection system that can detect 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 nuclear reaction rate at which a proton trap is incorporated on a sugar chlorine isotope.33).
“We, in turn, were able to calculate the ratios of various sulfur isotopes produced in stellar explosions, allowing astrophysicists to determine whether a particular presolar nut is of nova or supernova origin,” Seweryniak said. The team also applied their acquired data to gain a deeper understanding of the synthesis of elements in stellar explosions.
The team plans to continue their research with GRETINA as part of a global effort to achieve a comprehensive understanding of nucleosynthesis of the elements in stellar explosions.
Reference: “Search for Nova Presolar Beads: Y-Ray Spectroscopy of 34Ar and its importance to the astrophysical 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 en 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 institutes include the University of Surrey (UK), University of York (UK), University of Simon Fraser (Canada), Louisiana State University (FS), University of North Carolina (FS), Duke University (FS), Universitat Politècnica de Catalunya (Spain), and Institut d’Estudis Espacials de Catalunya (Spain) ).
This research was supported by the DOE Office of Science.
