Physicists at the Australian National University and the University of Oslo have successfully reproduced the process by which stars create carbon through the Hoyle state, discovering that carbon is produced 34 percent faster than previously estimated. This significant finding enhances our understanding of nucleosynthesis and its implications for astrophysics. The research builds on previous evaluations of thermonuclear reaction rates, emphasizing the importance of both direct and indirect measurement methods in nuclear astrophysics. This breakthrough not only impacts stellar evolution studies but also offers insights into physics beyond the standard model.
PREREQUISITESAstronomers, astrophysicists, and researchers in nuclear physics who are interested in the processes of element formation in stars and the implications for broader physical theories.
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.
New evaluation of thermonuclear reaction rates now includes the associated rate uncertainties that are used in astrophysical models to i) estimate final uncertainties on nucleosynthesis yields and ii) identify those reactions that require further experimental investigation. Sometimes direct cross section measurements are possible, but more generally the use of indirect methods is compulsory in view of the very low cross sections. Non-thermal processes are often overlooked but are also important for nuclear astrophysics, e.g. in gamma-ray emission from solar flares or in the interaction of cosmic rays with matter, and also motivate laboratory experiments. Finally, we show that beyond the historical motivations of nuclear astrophysics, understanding i) the energy sources that drive stellar evolution and ii) the origin of the elements can also be used to give new insights into physics beyond the standard model.
"Nobody had looked at this particular measurement since 1976. Everyone assumed it was well known."