Nuclear Astrophysics

How are the elements formed and distributed in the universe?

Nucleosynthesis that occurred during the cooling following the Big Bang gave rise to primordial abundances of the lightest elements H, He, and Li. Nearly all other chemical elements in the universe are produced as a result of nuclear reactions in stars or cataclysmic events events at the end of a star's life. The reaction products are expelled into the interstellar medium by stellar winds or events such as nova and supernova explosions, and neutron star mergers.

A central goal of astrophysics is to explain the origin and distribution of matter in the universe. Key areas of study include the origin of elements, the connection between the observed solar abundances and nuclear structure, the mechanism of core-collapse supernovae, the structure and cooling of neutron stars, and the equation of state for asymmetric nuclear matter.

Nuclear astrophysics has benefited enormously from progress in astronomical observation and astrophysical modelling, and a new era in nuclear astrophysics has opened with the use of radioactive beam (RIB) facilities dedicated to the measurement of short-lived nuclides of astrophysical relevance. These include the determination of masses, half-lives, the structure of exotic nuclei, and the direct and indirect determination of the various cross sections involving radioactive nuclei. The nuclear astrophysics measurements at TRIUMF and other international RIB facilities form an integral part of their science programs. Much of the instrumentation employed is also used for nuclear structure research.

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