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.Atomic mass of all elements (along with the rounded off values) is mentioned in the chart below. The stars were known to have heavy elements formed by the r-process in earlier generations of stars. The team took a fresh look at the amounts of heavy elements in 42 well-studied stars in the Milky Way. "We don't have a good sense of how many different kinds of sites in the universe can generate the r-process, we don't know how the r-process ends, and we can't 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." "We have a general idea of how the r-process works, but the conditions of the process are quite extreme," Roederer says. "And 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. "You 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," Roederer says. Roederer was previously at the University of Michigan. "The r-process is necessary if you want to make elements that are heavier than, say, lead and bismuth," says Ian Roederer, associate professor of physics at North Carolina State University and lead author of the research. One way that they do this is by splitting, a process called fission. The heaviest elements are unstable or radioactive, meaning they decay over time. Suddenly, a bunch of those neutrons get stuck to the nucleus in a very short time period - usually in less than one second - then undergo some internal neutron-to-proton changes, and voila! A heavy element, such as gold, platinum or uranium, forms. Picture a single atomic nucleus floating in a soup of neutrons. ![]() The heaviest elements are only known to be created in neutron stars via the rapid neutron capture process, or r-process. Broadly speaking, atomic mass is based on the number of protons and neutrons in the nucleus of one atom of that element. When we refer to light or heavy elements, we're talking about their atomic mass. Stars are element factories, where elements constantly fuse or break apart to create other lighter or heavier elements.
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