{"id":1192,"date":"2023-12-07T14:08:21","date_gmt":"2023-12-07T19:08:21","guid":{"rendered":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/2023\/12\/07\/ancient-stars-made-extraordinarily-heavy-elements\/"},"modified":"2026-05-21T00:09:58","modified_gmt":"2026-05-21T04:09:58","slug":"ancient-stars-made-extraordinarily-heavy-elements","status":"publish","type":"post","link":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/2023\/12\/07\/ancient-stars-made-extraordinarily-heavy-elements\/","title":{"rendered":"Ancient Stars Made Extraordinarily Heavy Elements"},"content":{"rendered":"\n\n\n\n\n

For Immediate Release<\/h2>\n
Tracey Peake<\/span>tracey_peake@ncsu.edu<\/a><\/div>\n\n\n\n
Ian Roederer<\/span>iuroederer@ncsu.edu<\/a><\/div>\n<\/section>\n\n\n\n

How heavy can an element be? An international team of researchers has found that ancient stars were capable of producing elements with atomic masses greater than 260, heavier than any element on the periodic table found naturally on Earth. The finding deepens our understanding of element formation in stars.<\/p>\n\n\n\n

We are, literally, made of star stuff. Stars are element factories, where elements constantly fuse or break apart to create other lighter or heavier elements. When we refer to light or heavy elements, we\u2019re talking about their atomic mass. Broadly speaking, atomic mass is based on the number of protons and neutrons in the nucleus of one atom of that element.<\/p>\n\n\n\n

The heaviest elements are only known to be created in neutron stars via the rapid neutron capture process, or r-process. Picture a single atomic nucleus floating in a soup of neutrons. Suddenly, a bunch of those neutrons get stuck to the nucleus in a very short time period \u2013 usually in less than one second \u2013 then undergo some internal neutron-to-proton changes, and voila! A heavy element, such as gold, platinum or uranium, forms.<\/p>\n\n\n\n

The heaviest elements are unstable or radioactive, meaning they decay over time. One way that they do this is by splitting, a process called fission.<\/p>\n\n\n\n

\u201cThe r-process is necessary if you want to make elements that are heavier than, say, lead and bismuth,\u201d says Ian Roederer, associate professor of physics at North Carolina State University and lead author of the research. Roederer was previously at the University of Michigan.<\/p>\n\n\n\n

\u201cYou have to add many neutrons very quickly, but the catch is that you need a lot of energy and a lot of neutrons to do so,\u201d Roederer says. \u201cAnd the best place to find both are at the birth or death of a neutron star, or when neutron stars collide and produce the raw ingredients for the process.<\/p>\n\n\n\n

\u201cWe have a general idea of how the r-process works, but the conditions of the process are quite extreme,\u201d Roederer says. \u201cWe don\u2019t have a good sense of how many different kinds of sites in the universe can generate the r-process, we don\u2019t know how the r-process ends, and we can\u2019t answer questions like, how many neutrons can you add? Or, how heavy can an element be? So we decided to look at elements that could be made by fission in some well-studied old stars to see if we could start to answer some of these questions.\u201d<\/p>\n\n\n\n

The team took a fresh look at the amounts of heavy elements in 42 well-studied stars in the Milky Way. The stars were known to have heavy elements formed by the r-process in earlier generations of stars. By taking a broader view of the amounts of each heavy element found in these stars collectively, rather than individually as is more common, they identified previously unrecognized patterns.<\/p>\n\n\n\n

Those patterns signaled that some elements listed near the middle of the periodic table \u2013 such as silver and rhodium \u2013 were likely the remnants of heavy element fission. The team was able to determine that the r-process can produce atoms with an atomic mass of at least 260 before they fission.<\/p>\n\n\n\n

\u201cThat 260 is interesting because we haven\u2019t previously detected anything that heavy in space or naturally on Earth, even in nuclear weapon tests,\u201d Roederer says. \u201cBut seeing them in space gives us guidance for how to think about models and fission \u2013 and could give us insight into how the rich diversity of elements came to be.\u201d<\/p>\n\n\n\n

The work appears in Science<\/a><\/em> and was supported in part by the National Science Foundation and the National Aeronautics and Space Administration.<\/p>\n\n\n\n

-peake-<\/p>\n\n\n\n

Note to editors:<\/strong> An abstract follows.<\/p>\n\n\n\n

\u201cElement abundance patterns in stars indicate fission of nuclei heavier than uranium\u201d<\/strong><\/p>\n\n\n\n

DOI:<\/strong> 10.1126\/science.adf1341<\/a><\/p>\n\n\n\n

Authors:<\/em> Ian U. Roederer, North Carolina State University; Nicole Vassh, TRIUMF (Tri-University Meson Facility) Vancouver, Canada; Erika M. Holmbeck, Carnegie Observatories, California; Matthew R. Mumpower, Los Alamos National Laboratory; Rebecca Surman, University of Notre Dame; John J. Cowan, University of Oklahoma; Timothy C. Beers, University of Notre Dame; Rana Ezzeddine, University of Florida; Anna Frebel, Massachusetts Institute of Technology; Terese T. Hansen, Stockholm University, Sweden; Vinicius M. Placco, NSF\u2019s National Optical-Infrared Astronomy Research Laboratory; Charli M. Sakari, San Francisco State University
Published:<\/em> Dec. 7, 2023 in Science<\/em><\/p>\n\n\n\n

Abstract:<\/strong>
The heaviest chemical elements are naturally produced by the rapid neutron-capture process (r-process) during neutron star mergers or supernovae. The r-process production of elements heavier than uranium (transuranic nuclei) is poorly understood and inaccessible to experiments so must be extrapolated by using nucleosynthesis models. We examined element abundances in a sample of stars that are enhanced in r-process elements. The abundances of elements ruthenium, rhodium, palladium, and silver (atomic numbers Z = 44 to 47; mass numbers A = 99 to 110) correlate with those of heavier elements (63 \u2264 Z \u2264 78, A > 150). There is no correlation for neighboring elements (34 \u2264 Z \u2264 42 and 48 \u2264 Z \u2264 62). We interpret this as evidence that fission fragments of transuranic nuclei contribute to the abundances. Our results indicate that neutron-rich nuclei with mass numbers >260 are produced in r-process events.<\/p>\n

This post was originally published<\/a> in NC State News.<\/em><\/p>","protected":false,"raw":"\n\n\n\n\n

For Immediate Release<\/h2>\n
Tracey Peake<\/span>tracey_peake@ncsu.edu<\/a><\/div>\n\n\n\n
Ian Roederer<\/span>iuroederer@ncsu.edu<\/a><\/div>\n<\/section>\n\n\n\n

How heavy can an element be? An international team of researchers has found that ancient stars were capable of producing elements with atomic masses greater than 260, heavier than any element on the periodic table found naturally on Earth. The finding deepens our understanding of element formation in stars.<\/p>\n\n\n\n

We are, literally, made of star stuff. Stars are element factories, where elements constantly fuse or break apart to create other lighter or heavier elements. When we refer to light or heavy elements, we\u2019re talking about their atomic mass. Broadly speaking, atomic mass is based on the number of protons and neutrons in the nucleus of one atom of that element.<\/p>\n\n\n\n

The heaviest elements are only known to be created in neutron stars via the rapid neutron capture process, or r-process. Picture a single atomic nucleus floating in a soup of neutrons. Suddenly, a bunch of those neutrons get stuck to the nucleus in a very short time period \u2013 usually in less than one second \u2013 then undergo some internal neutron-to-proton changes, and voila! A heavy element, such as gold, platinum or uranium, forms.<\/p>\n\n\n\n

The heaviest elements are unstable or radioactive, meaning they decay over time. One way that they do this is by splitting, a process called fission.<\/p>\n\n\n\n

\u201cThe r-process is necessary if you want to make elements that are heavier than, say, lead and bismuth,\u201d says Ian Roederer, associate professor of physics at North Carolina State University and lead author of the research. Roederer was previously at the University of Michigan.<\/p>\n\n\n\n

\u201cYou have to add many neutrons very quickly, but the catch is that you need a lot of energy and a lot of neutrons to do so,\u201d Roederer says. \u201cAnd the best place to find both are at the birth or death of a neutron star, or when neutron stars collide and produce the raw ingredients for the process.<\/p>\n\n\n\n

\u201cWe have a general idea of how the r-process works, but the conditions of the process are quite extreme,\u201d Roederer says. \u201cWe don\u2019t have a good sense of how many different kinds of sites in the universe can generate the r-process, we don\u2019t know how the r-process ends, and we can\u2019t answer questions like, how many neutrons can you add? Or, how heavy can an element be? So we decided to look at elements that could be made by fission in some well-studied old stars to see if we could start to answer some of these questions.\u201d<\/p>\n\n\n\n

The team took a fresh look at the amounts of heavy elements in 42 well-studied stars in the Milky Way. The stars were known to have heavy elements formed by the r-process in earlier generations of stars. By taking a broader view of the amounts of each heavy element found in these stars collectively, rather than individually as is more common, they identified previously unrecognized patterns.<\/p>\n\n\n\n

Those patterns signaled that some elements listed near the middle of the periodic table \u2013 such as silver and rhodium \u2013 were likely the remnants of heavy element fission. The team was able to determine that the r-process can produce atoms with an atomic mass of at least 260 before they fission.<\/p>\n\n\n\n

\u201cThat 260 is interesting because we haven\u2019t previously detected anything that heavy in space or naturally on Earth, even in nuclear weapon tests,\u201d Roederer says. \u201cBut seeing them in space gives us guidance for how to think about models and fission \u2013 and could give us insight into how the rich diversity of elements came to be.\u201d<\/p>\n\n\n\n

The work appears in Science<\/a><\/em> and was supported in part by the National Science Foundation and the National Aeronautics and Space Administration.<\/p>\n\n\n\n

-peake-<\/p>\n\n\n\n

Note to editors:<\/strong> An abstract follows.<\/p>\n\n\n\n

\u201cElement abundance patterns in stars indicate fission of nuclei heavier than uranium\u201d<\/strong><\/p>\n\n\n\n

DOI:<\/strong> 10.1126\/science.adf1341<\/a><\/p>\n\n\n\n

Authors:<\/em> Ian U. Roederer, North Carolina State University; Nicole Vassh, TRIUMF (Tri-University Meson Facility) Vancouver, Canada; Erika M. Holmbeck, Carnegie Observatories, California; Matthew R. Mumpower, Los Alamos National Laboratory; Rebecca Surman, University of Notre Dame; John J. Cowan, University of Oklahoma; Timothy C. Beers, University of Notre Dame; Rana Ezzeddine, University of Florida; Anna Frebel, Massachusetts Institute of Technology; Terese T. Hansen, Stockholm University, Sweden; Vinicius M. Placco, NSF\u2019s National Optical-Infrared Astronomy Research Laboratory; Charli M. Sakari, San Francisco State University
Published:<\/em> Dec. 7, 2023 in Science<\/em><\/p>\n\n\n\n

Abstract:<\/strong>
The heaviest chemical elements are naturally produced by the rapid neutron-capture process (r-process) during neutron star mergers or supernovae. The r-process production of elements heavier than uranium (transuranic nuclei) is poorly understood and inaccessible to experiments so must be extrapolated by using nucleosynthesis models. We examined element abundances in a sample of stars that are enhanced in r-process elements. The abundances of elements ruthenium, rhodium, palladium, and silver (atomic numbers Z = 44 to 47; mass numbers A = 99 to 110) correlate with those of heavier elements (63 \u2264 Z \u2264 78, A > 150). There is no correlation for neighboring elements (34 \u2264 Z \u2264 42 and 48 \u2264 Z \u2264 62). We interpret this as evidence that fission fragments of transuranic nuclei contribute to the abundances. Our results indicate that neutron-rich nuclei with mass numbers >260 are produced in r-process events.<\/p>\n"},"excerpt":{"rendered":"

How heavy can an element be? Ancient stars were capable of producing elements heavier than any element on the periodic table found naturally on Earth.<\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"source":"ncstate_wire","ncst_dynamicHeaderBlockName":"","ncst_dynamicHeaderData":"","ncst_content_audit_freq":"","ncst_content_audit_date":"","ncst_content_audit_display":false,"ncst_backToTopFlag":"","footnotes":""},"categories":[1],"tags":[5],"class_list":["post-1192","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-_from-newswire-collection-6"],"displayCategory":null,"acf":[],"_links":{"self":[{"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/posts\/1192","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/comments?post=1192"}],"version-history":[{"count":4,"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/posts\/1192\/revisions"}],"predecessor-version":[{"id":2491,"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/posts\/1192\/revisions\/2491"}],"wp:attachment":[{"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/media?parent=1192"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/categories?post=1192"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dev.ucomm.ncsu.edu\/web-platform-free-tier\/wp-json\/wp\/v2\/tags?post=1192"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}