Astro talk - Carl R. Brune: "4He+12C fusion in Massive Stars"
Oplysninger om arrangementet
Carl R. Brune
Ohio University, USA
4He+12C fusion in Massive Stars
The 12C(alpha,gamma)16O reaction, along with the triple-alpha process, determines the 12C/16O ratio at the end of stellar helium burning. These isotopes are the seeds for subsequent evolution stages. Consequently, the 12C(alpha,gamma) reaction rate strongly influences many aspects of the life of a massive star. The cross section at astrophysical energies is far too small to be measured directly and must be estimated from measurements at higher energies and various indirect observables. This talk will summarize our current knowledge of this reaction and and provide some details on relevant experiments that we have performed: measurement of
the anisotropy of the 2.68-keV resonance, alpha-transfer reactions, and direct at higher energies using a recoil separator.