Alpha-constrained QSE Nucleosynthesis in High-entropy and Fast-expanding Material
Abstract
We investigate the nucleosynthesis process in high-entropy (
s/
k
B
≳100
) and very fast-expanding (
τ
exp
∼
10
−3
s
) materials. In such a material with the electron fraction near 0.5, an interesting nucleosynthesis process occurs. In this process, the abundance distribution of heavy-nuclei of
A>100
achieve quasi-statistical equilibrium (QSE) at high temperature and the abundances are frozen at the end of the nucleosynthesis. We explain this abundance distribution using the "alpha-constrained QSE" abundances formulated in this paper. We demonstrate that this nucleosynthesis would occur in neutrino-driven winds from massive proto-neutron stars in hypernovae, where
A∼140
p
-nuclei are synthesized.