Nuclear Physics Division

One of the major issues in modern astrophysics concerns the analysis and understanding of the present composition of the Universe and its various constituting objects.
Nucleosynthesis models aim to explain the origin of the different nuclei observed in nature by identifying the possible processes able to synthesize them. Though the origin of most of the nuclides lighter than iron through the various hydrostatic and explosive burning stages in stars is now quite well understood, the synthesis of the heavy elements (i.e. heavier than iron) remains obscure in many respects. The major mechanisms called for to explain the production of the heavy nuclei are i) the slow neutron-capture process (or s-process) occurring during specific hydrostatic stellar burning phases, ii) the rapid neutron-capture process (or r-process) believed to develop during the explosion of a star as a type II supernova or during the merging of two compact objects, and iii) the photo-disintegration process (or p-process) taking place in the high-temperature environment of type-Ia or type-II supernovae. The stellar nucleosynthesis requires a detailed knowledge not only of the astrophysical sites and physical conditions in which the processes take place, but also the nuclear structure and interaction properties for all the nuclei involved.

This seminar describes our present understanding of the stellar nucleosynthesis processes as well as the many experimental and theoretical efforts devoted to determine the related nuclear physics inputs of relevance. These include nuclear structure as well as decay and reaction properties of relevance in astrophysical environments. A special attention will be paid to the complex physics related to the r-process nucleosynthesis and the new developments in the light of the recent observation of the binary neutron star merger GW170817.

This seminar is organized in the framework of the first session (7-8^th December 2017) of the ESNT workshop on "nuclear data inputs and astrophysical processes". Lectures on this subject will be given in the morning and afternoon sessions on 7th December by S. Goriely. The detailed program is available on: http://esnt.cea.fr/Phocea/Page/index.php?id=76

Web Site of ESNT, "Espace de Structure et de réactions Nucléaires Théorique": http://esnt.cea.fr