Dynamical r-process studies within the neutrino-driven wind scenario and its sensitivity to the nuclear physics input

Journal Article · Fri Apr 15 00:00:00 EDT 2011 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.83.045809· OSTI ID:21499635

Arcones, A ^[1]; Martinez-Pinedo, G ^[2]

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1. Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany)
2. GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstrasse 1, D-64291 Darmstadt (Germany)

We use results from long-time core-collapse supernovae simulations to investigate the impact of the late time evolution of the ejecta and of the nuclear physics input on the calculated r-process abundances. Based on the latest hydrodynamical simulations, heavy r-process elements cannot be synthesized in the neutrino-driven winds that follow the supernova explosion. However, by artificially increasing the wind entropy, elements up to A=195 can be made. In this way one can reproduce the typical behavior of high-entropy ejecta where the r process is expected to occur. We identify which nuclear physics input is more important depending on the dynamical evolution of the ejecta. When the evolution proceeds at high temperatures (hot r process), an (n,{gamma})<-->({gamma},n) equilibrium is reached, while at low temperatures (cold r process) there is a competition between neutron captures and beta decays. In the first phase of the r process, while enough neutrons are available, the most relevant nuclear physics inputs are the nuclear masses for the hot r process and the neutron capture and beta-decay rates for the cold r process. At the end of this phase, the abundances follow a steady beta flow for the hot r process and a steady flow of neutron captures and beta decays for the cold r process. After neutrons are almost exhausted, matter decays to stability and our results show that in both cases neutron captures are key for determining the final abundances, the position of the r-process peaks, and the formation of the rare-earth peak. In all the cases studied, we find that the freeze-out occurs in a time scale of several seconds.

• OSTI ID: 21499635
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 83, Issue 4; Other Information: DOI: 10.1103/PhysRevC.83.045809; (c) 2011 American Institute of Physics; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BETA DECAY
ENTROPY
EQUILIBRIUM
FREEZING OUT
GAMMA DECAY
HYDRODYNAMIC MODEL
MASS
NEUTRINOS
NEUTRON EMISSION
NEUTRON REACTIONS
NEUTRONS
NUCLEAR PHYSICS
PHOTONUCLEAR REACTIONS
R PROCESS
RARE EARTHS
SENSITIVITY
SIMULATION
STEADY FLOW
SUPERNOVAE
BARYON REACTIONS
BARYONS
BINARY STARS
DECAY
ELEMENTARY PARTICLES
ELEMENTS
EMISSION
ERUPTIVE VARIABLE STARS
EVOLUTION
FERMIONS
FLUID FLOW
HADRON REACTIONS
HADRONS
LEPTONS
MASSLESS PARTICLES
MATHEMATICAL MODELS
METALS
NUCLEAR DECAY
NUCLEAR REACTIONS
NUCLEON REACTIONS
NUCLEONS
PARTICLE MODELS
PHYSICAL PROPERTIES
PHYSICS
SEPARATION PROCESSES
STAR EVOLUTION
STARS
STATISTICAL MODELS
THERMODYNAMIC MODEL
THERMODYNAMIC PROPERTIES
VARIABLE STARS