Аннотация:

The US science academies report on «Connecting Quarks to the Cosmos» identified eleven of the most challenging open questions for all of physics in the 21st century. One of these eleven questions included the identification of the site(s) for the production of the heaviest elements found in nature.
Most of the elements above Fe are thought to have been produced by either the slow (s-process) or rapid (r-process) capture of neutrons in astrophysical environments. The sprocess proceeds close to stability and astrophysical sites have been identified, while the rprocess allows the production of nuclei much further from stability and potential sites remain mostly unresolved.
Nuclear masses, beta-decay rates, and neutron-capture cross-sections play an important role in identifying the astrophysical constraints for a possible site for the r-process. Many of the nuclei that may be involved in an r-process lie far from stability and themselves present a challenge and impetus to experimental nuclear physics. Nuclear mass models and mass measurements have a pivotal role in both the impetus side of experiments and the simulation or constraint side of astrophysical site calculations. We identify key nuclei in the study whose mass has a substantial impact on final r-process abundances and thereby set strict constraints on the astrophysical trajectories that have been considered while highlighting the nuclei that could be measured at present and future radioactive beam facilities around the world.
The recent observation of gravitational waves from two neutron star mergers simultaneously with the spectroscopy showed lines from rare earth elements. The questions remain:

• are there enough such mergers?
• are mergers the only source of r-process elements?