Fine-grid calculations for stellar electron and positron capture rates on Fe isotopes

Journal Article · Fri Mar 15 04:00:00 EDT 2013 · Physics of Atomic Nuclei

DOI:https://doi.org/10.1134/S1063778813020142· OSTI ID:22156404

Nabi, Jameel-Un ^[1]

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1. Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Faculty of Engineering Sciences (Pakistan)

The acquisition of precise and reliable nuclear data is a prerequisite to success for stellar evolution and nucleosynthesis studies. Core-collapse simulators find it challenging to generate an explosion from the collapse of the core of massive stars. It is believed that a better understanding of the microphysics of core-collapse can lead to successful results. The weak interaction processes are able to trigger the collapse and control the lepton-to-baryon ratio (Y{sub e}) of the corematerial. It is suggested that the temporal variation of Y{sub e} within the core of a massive star has a pivotal role to play in the stellar evolution and a fine-tuning of this parameter at various stages of presupernova evolution is the key to generate an explosion. During the presupernova evolution of massive stars, isotopes of iron, mainly {sup 54-56}Fe, are considered to be key players in controlling Y{sub e} ratio via electron capture on these nuclides. Recently an improved microscopic calculation of weak-interaction-mediated rates for iron isotopes was introduced using the proton-neutron quasiparticle random-phase-approximation (pn-QRPA) theory. The pn-QRPA theory allows a microscopic state-by-state calculation of stellar capture rates which greatly increases the reliability of calculated rates. The results were suggestive of some fine-tuning of the Y{sub e} ratio during various phases of stellar evolution. Here we present for the first time the fine-grid calculation of the electron and positron capture rates on {sup 54-56}Fe. The sensitivity of the pn-QRPA calculated capture rates to the deformation parameter is also studied in this work. Core-collapse simulators may find this calculation suitable for interpolation purposes and for necessary incorporation in the stellar evolution codes.

• OSTI ID: 22156404
• Journal Information: Physics of Atomic Nuclei, Journal Name: Physics of Atomic Nuclei Journal Issue: 3 Vol. 76; ISSN 1063-7788; ISSN PANUEO
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
COSMIC ELECTRONS
COSMIC POSITRONS
DEFORMATION
ELECTRON CAPTURE
EXPLOSIONS
INTERPOLATION
IRON 54
IRON 55
IRON 56
IRON ISOTOPES
NEUTRONS
NUCLEOSYNTHESIS
PROTONS
RANDOM PHASE APPROXIMATION
RELIABILITY
SENSITIVITY
SIMULATORS
STAR EVOLUTION
STARS
WEAK INTERACTIONS