Australian National University | 2020 Oct 08
A new measurement of how quickly stars create carbon may trigger a major shift in our understanding of how stars evolve and die, how the elements are created, and even the origin and abundance of the building blocks of life.
Physicists at the Australian National University and the University of Oslo reproduced how stars make carbon through a fleeting partnership of helium atoms known as the Hoyle state in two separate measurements. They found that carbon – the building block of life – is produced 34 percent faster than previously thought. ...
Stars produce carbon through the triple-alpha process, where three alpha particles (helium nuclei) collide and fuse within a tiny fraction of a second. This process is so unlikely that for many years astrophysicists were at a loss to explain how carbon and heavier elements could be created in the universe.
In 1953 renowned astronomer Sir Fred Hoyle suggested a solution to the conundrum: a previously unknown excited state of carbon, very close to the energy of the triple alpha process. This excited state, now known as the Hoyle state, and would act as a stepping stone to producing stable carbon.
This in turn paves the way for further fusion reactions, allowing stars to make the heavier elements from oxygen to iron and beyond. ...
Radiative Width of the Hoyle State from γ-ray Spectroscopy ~ T. Kibédi et al
- arXiv.org > nucl-ex > arXiv:2009.10915 > 23 Sep 2020