Joint Institute for Nuclear Astrophysics established

Author: William G. Gilroy

The National Science Foundation (NSF) has awarded $10 million to the University of Notre Dame, Michigan State University and the University of Chicago to establish a Physics Frontier Center for Nuclear Astrophysics.p. Known as JINA – The Joint Institute for Nuclear Astrophysics the center is a collaborative effort of the three universities. Michael Wiescher, a Notre Dame nuclear astrophysicist and last year’s winner of the prestigious Bethe Prize of the American Physical Society, will serve as JINA’s first director.p. According to Wiescher, the five-year NSF grant is intended to foster an interdisciplinary approach to nuclear astrophysics that seeks to coordinate efforts between the astrophysics and nuclear physics communities, as well as those between experimentalists, theorists and observers. The $10-million grant to JINA comes at a time when new generations of particle accelerators are being built or proposed that will recreate stellar nuclear processes in the laboratory and new earth and space-based telescopes are leading to astronomical observations that trace past and present nucleosynthesis processes in the cosmos.p. The scientific goal of JINA is to study the broad range of nuclear processes in the universe that control stellar evolution, trigger supernova events, and lead to thermonuclear explosions observed as novae, X-ray and Y-ray bursts. Research at JINA also will involve investigators from the University of California at Santa Cruz, the University of California at Santa Barbara and the University of Arizona to address the broad range of computational problems in realistic modeling of nucleosynthesis in stars and stellar explosions.p. “Simulating nuclear processes within supernovae and in the outer atmospheres of accreting neutron stars is complex and formidable,? Wiescher said. ?We will need the computational techniques presently being developed at the University of Chicago and Notre Dame to design models that will enable us to simulate realistically the nucleosynthesis in stars and stellar explosions such as supernovae.”p. JINA researchers also will focus on exotic nuclear explosions that occur on the surfaces of compact stellar objects, such as white dwarfs or even neutron stars, that collect matter from a nearby binary companion star.p. “We now have observatories in orbit that obtain detailed measurements of X-ray emission from such compact objects, but we lack the knowledge of the underlying exotic nuclear physics necessary to effectively use these observations as unique laboratories for the study of the behavior of matter under extreme conditions,” said Hendrik Schatz, a nuclear astrophysicist at Michigan State and head of one of JINA’s main research components.p. The University of Chicago’s James Truran, a JINA co-investigator, will lead these theoretical efforts to provide a better understanding of the astronomical environments – massive stars, supernovae explosions, X-ray bursts and novae – in which the nuclear processes are understood to operate.p. “Multidimensional computer simulations of astrophysical explosions are now providing more realistic estimates of the extreme conditions of temperature and density under which heavy elements are formed in stars and supernovae,” Truran said.p. The experimental simulation of nuclear processes at stellar conditions will be performed at accelerator facilities at Notre Dame, Michigan State and the Argonne National Laboratory. It requires new experimental techniques for accelerating radioactive isotopes for measuring processes that in nature take place only at the extreme conditions of supernovae explosions, or performing experiments thousands of feet underground to reduce the background noise of cosmic bombardment.p. A significant part of the NSF funds will go toward the development of such new techniques and instrumentation at the three nuclear physics accelerators on Notre Dame’s campus to study the processes taking place deep inside the core of our sun and other stars. It also includes detector development at the coupled cyclotron facility at Michigan State to study nuclear processes during stellar explosions. These measurements are essential for interpreting the broad range of observational results in the context of present model simulations. These experimental efforts are a critical component of the entire scientific program at JINA.p. “Both the experimental and theoretical studies in nuclear astrophysics at JINA will provide the basis for an understanding of the detailed nuclear processes involved in the origin of the elements,” Turran said.p. One of the mysteries JINA seeks to address is the question of the origin of the chemical elements, in particular the nucleosynthesis of heavy elements, such as gold and uranium.p. “We still don’t understand why there is so much gold in the universe,” Schatz said. “We know these heavy elements are the decay products of very exotic atomic nuclei, but exactly how and where in the universe these have been created still remains an open question. The experimental and theoretical studies in nuclear physics associated with JINA will provide the basis for an understanding of the detailed nuclear processes involved in the origin of the elements.”p. Complementing the theoretical and experimental efforts at JINA, Timothy C. Beers of Michigan State is leading a survey of element production in the early galaxy, as revealed in the spectra of ancient stars. His recent detection of radioactive elements, such as uranium and thorium, in the oldest stars in the galaxy also provides a valuable means to obtain independent estimates of the age of the universe.p. "High-resolution spectroscopic observations of the oldest stars in our Galaxy, made with the Hubble Space Telescope and 8m-class telescopes such as the European VLT, have revealed the presence of the very first heavy elements in the universe,? Beers said. “We are using these data to infer the ‘recipe of creation,’ the fundamental ingredients from which, eventually, all elements heavier than hydrogen and helium are formed.”p. According to Ani Aprahamian, professor and chair of physics at Notre Dame and head of one of the main research components of JINA, the NSF grant will enable JINA to join together research efforts in separate disciplines ranging from astronomy to astrophysics to nuclear physics.p. “These areas have, until now, basically followed separate paths,” she said. “This award will enable the emergence of a new area of study. The consolidation of all three disciplines will provide faster resolution of common challenges.”p. The Physics Frontiers program at NSF was created to support research in making transformational advances in the most promising new scientific areas. This is a way to enable major scientific advances at the intellectual frontiers of physics by providing new resources, not usually available to individual investigators or small university research groups, to advance our understanding of the universe.p. The JINA Physics Frontier Center will engage in many outreach activities aimed at making these scientific goals and advances accessible to the public, educators and students of all levels. It seeks also to provide research opportunities for high school students and teachers as well as for undergraduates from colleges in the Midwest. For more information on JINA, visit .

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