Neutron sources and neutron-capture paths in asymptotic giant branch stars

8th European Summer School on Experimental Nuclear Astrophysics (Santa Tecla School)

物理学;天文学

Maria, Lugaro^1,2

Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Budapest

H-1121, Hungary^1

Monash Centre for Astrophysics, Monash University

VIC

3800, Australia^2

关键词: AGB stars;    Asymptotic giant branch stars;    Hydrostatic conditions;    Neutron capture;    Neutron density;    Neutron-capture process;    Slow neutrons;    Stellar rotation;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/703/1/012003/pdf
DOI  :  10.1088/1742-6596/703/1/012003

学科分类：天文学(综合)

来源: IOP

【 摘 要 】

Roughly half of the abundances of the elements heavier than iron in the cosmos are produced by slow neutron captures (the s process) in hydrostatic conditions when the neutron density is below roughly 1013n/cm-3. While it is observationally well confirmed that asymptotic giant branch (AGB) stars are the main site of the s process, we are still facing many problems in the theoretical models and nuclear inputs. Major current issues are the effect of stellar rotation and magnetic fields and the determination of the rate of the neutron source reactions. I will present these problems and discuss the observational constraints that can help us to solve them, including spectroscopically derived abundances, meteoritic stardust, and stellar seismology. Further, I will present evidence that the s process is not the only neutron-capture process to occur in AGB stars: an intermediate process is also required to explain recent observations of post-AGB stars.