Origin of the heavy elements in binary neutron-star mergers from a gravitational wave event

Understand

The cosmic origin of the elements heavier than iron has long been uncertain.

• Theoretical modelling shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum in a process known as rapid neutron capture (r-process) nucleosynthesis.
• The radioactive decay of isotopes of the heavy elements is predicted to power a distinctive thermal glow (a 'kilonova').
• The discovery of an electromagnetic counterpart to the gravitational-wave source GW170817 represents the first opportunity to detect and scrutinize a sample of freshly synthesized r-process elements.