Sensitivity of r-Process Nucleosynthesis to Light-Element Nuclear Reactions

Abstract

We study the efficiency and sensitivity of r-process nucleosynthesis to 18 light-element nuclear reaction rates. We adopt empirical power-law relations to parameterize the reaction sensitivities. We utilize two different hydrodynamic models for the neutrino-driven winds in order to study the dependence of our result on supernova wind models. We also utilize an exponential model to approximate a wide variety of other plausible conditions for the r-process. We identify several specific nuclear reactions among light neutron-rich nuclei that play a critical role in determining the final r-process nucleosynthesis yields. As an illustration, we examine ``semi-waiting'' points among the carbon isotopes. We show that not only neutron capture and $\beta$-decay, but also $(\alpha ,\mathrm{n})$ reactions are important in determining waiting points along the r-process path. Our numerical results from this sensitivity analysis serve foremost to clarify which light nuclear reactions are most influential in determining the final r-process abundances. We also quantify the effects of present nuclear uncertainties on the final r-process abundances. This study thus emphasizes and motivates which future determinations of nuclear reaction rates will most strongly impact our understanding of r-process nucleosynthesis.

ApJ (2005) in press, 47pages, 13figures

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• Determination of the ${}^{36}$Mg($n,\gamma$)${}^{37}$Mg reaction rate from Coulomb dissociation of ${}^{37}$Mg
• Exploring the halo character and dipole response in the dripline nucleus ${}^{31}$F
• Influence of low-lying resonances on reaction rates for n10B capture
• Determination of the Neutron-Capture Rate of 17C for the R-process Nucleosynthesis
• Coulomb dissociation of ${}^{20,21}$N
• New Results for Neutron Radiative Capture on 10be at Energies from 25.3 meV to 10.0 meV
• A global study of ${}^9$Be + p at 2.72 A MeV
• Structural effects of ${}^{34}$Na in the ${}^{33}$Na(n,$\gamma {)}^{34}$Na radiative capture reaction
• Nuclear astrophysics with radioactive ions at FAIR
• Thermonuclear 17O(n,gamma)18O reaction rate and its astrophysical implications
• Role of resonances in the 8li(p,g)9be capture on reaction rate of the relevant astrophysical synthesis of 9be
• Manifestation of the divergence between antisymmetrized-molecular-dynamics and container pictures of ${}^9$Be via ${}^9$Be($p,pn$)${}^8$Be knockout reaction
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