Nuclear astrophysics

Nuclear astrophysics is an interdisciplinary branch of physics involving close collaboration among researchers in various subfields of nuclear physics and astrophysics: notably stellar modeling; measurement and theoretical estimation of nuclear reaction rates; physical cosmology and cosmochemistry; gamma ray, optical and X-ray astronomy; and extending our knowledge about nuclear lifetimes and masses. In general terms, nuclear astrophysics aims to understand the origin of the chemical elements and the energy generation in stars.The basic principles for explaining the origin of elements and energy generation in stars appear in the theory of nucleosynthesis, which came together in the late 1950s in seminal works by Burbidge, Burbidge, Fowler, and Hoyle, and by Cameron. Fowler is largely credited with initiating collaboration between astronomers, astrophysicists, and experimental nuclear physicists that we now know as nuclear astrophysics (for which he won the 1983 Nobel Prize).Stellar nucleosynthesis theory estimates chemical abundances consistent with those observed in the Solar System and galaxy, whose distribution spans twelve orders of magnitude (one trillion). While impressive, these data were used to formulate the theory, but a scientific theory must be predictive to have merit. The theory has been well-tested by observation and experiment since first formulated.Although the foundations of the science are bona fide, many questions still remain open. Some long-standing issues are helium fusion (specifically the 12C(α,γ)16O reaction), the astrophysical site of the r-process, anomalous lithium abundances in Population III stars, and the explosion mechanism in core-collapse supernovae.