Besides supernovae, what event generates extreme conditions necessary for intense *r*-process element creation?

Answer

Merging of neutron stars

When two neutron stars collide, the resulting environment provides the necessary extreme conditions for an intense rapid neutron capture process, leading to the creation of elements like gold and platinum.

Besides supernovae, what event generates extreme conditions necessary for intense *r*-process element creation?
starsstellar evolutionElementsnucleosynthesis