Kilonovae:
A kilonova (also called a macronova or r-process supernova) is a transient astronomical event that occurs in a compact binary system when two neutron stars or a neutron star and a black hole merge. Kilonovae are thought to emit short gamma-ray bursts and strong electromagnetic radiation due to the radioactive decay of heavy r-process nuclei that are produced and ejected fairly isotropically during the merger process. [Wikipedia]
Noted in “How does the sun shine? Here’s why we are still a little in the dark,” Chanda Prescod-Weinstein, NewScientist (22 January 2022):
Generally speaking, the reason stars shine is that gravity has pulled a sufficient amount of hydrogen atoms into such close quarters that they start to fuse together into helium. Every star starts this way. When the hydrogen runs out, the helium starts fusing together, and so on, producing heavier and heavier elements.
This is where we humans begin. The majority of the elements we are composed of are made in stars and, during supernovae and kilonovae, the exploding deaths of those massive stars.
This sounds like a simple matter of gluing elements together, but it isn’t: the conditions have to be just right. The hydrogen has to be hot enough and close enough together to fuse. And the fusion happens in stages. The theories that describe how all this happens aren’t the classical Newtonian physics that describes, for example, two football players colliding when they both want to control the ball. Instead, we need quantum mechanics and nuclear physics.
