R-process enrichment from a single event in an ancient dwarf galaxy

Understand

Elements heavier than zinc are synthesized through the (r)apid and (s)low neutron-capture processes.

• The main site of production of the r-process elements (such as europium) has been debated for nearly 60 years.
• Initial studies of chemical abundance trends in old Milky Way halo stars suggested continual r-process production, in sites like core-collapse supernovae.
• But evidence from the local Universe favors r-process production mainly during rare events, such as neutron star mergers.