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A neutron star merger is the stellar collision of neutron stars. When two neutron stars fall into mutual orbit, they gradually spiral inward due to the loss of energy emitted as gravitational radiation. [1] When they finally meet, their merger leads to the formation of either a more massive neutron star, or—if the mass of the remnant exceeds ...
Neutron star mergers are a recently discovered major source of elements produced in the r-process. When two neutron stars collide, a significant amount of neutron-rich matter may be ejected which then quickly forms heavy elements. Cosmic ray spallation is a process wherein cosmic rays impact nuclei and fragment them.
In astrophysics, stellar nucleosynthesis is the creation of chemical elements by nuclear fusion reactions within stars. Stellar nucleosynthesis has occurred since the original creation of hydrogen, helium and lithium during the Big Bang. As a predictive theory, it yields accurate estimates of the observed abundances of the elements.
Helium, oxygen, neon, iron—they all come from the fusion that takes place in dying stars. But we have a lot of elements that are more massive than iron ; it’s only element 26 of 118, after all.
There are three natural candidate sites for r-process nucleosynthesis where the required conditions are thought to exist: low-mass supernovae, Type II supernovae, and neutron star mergers. [ 15 ] Immediately after the severe compression of electrons in a Type II supernova, beta-minus decay is blocked.
Electromagnetic observations help support the theory that neutron star mergers contribute to rapid neutron capture (r-process) nucleosynthesis [28] —previously assumed to be associated with supernova explosions—and are therefore the primary source of r-process elements heavier than iron, [1] including gold and platinum. [48]
In July 2019, astronomers reported that a new method to determine the Hubble constant, and resolve the discrepancy of earlier methods, has been proposed based on the mergers of pairs of neutron stars, following the detection of the neutron star merger of GW170817. [108] [109] Their measurement of the Hubble constant is 70.3 +5.3 −5.0 (km/s ...
Supernova nucleosynthesis is the nucleosynthesis of chemical elements in supernova explosions.. In sufficiently massive stars, the nucleosynthesis by fusion of lighter elements into heavier ones occurs during sequential hydrostatic burning processes called helium burning, carbon burning, oxygen burning, and silicon burning, in which the byproducts of one nuclear fuel become, after ...