Screening Effects on Electron Capture Rates and Type Ia Supernova Nucleosynthesis

Abstract

Type Ia supernovae (SNe Ia) are believed to be a thermonuclear explosion of a white dwarf, but the mass of their progenitors is still an open problem. In near-Chandrasekhar-mass (near-M_Ch) models of SNe Ia, the central density reaches >10^9 g cm^{-3}. The electron chemical potential becomes higher than the Q-values of electron capture (EC) transitions between fp-shell nuclei, so a portion of the available electrons is captured by iron group elements and thus neutron-rich isotopes are formed. Since EC reaction rates are sensitive to the density, the degree of neutronization is a key to distinguish near- and sub-M_Ch models. In order to compare observations and theoretical models, an accurate treatment of EC reactions is necessary. In previous theoretical works, however, effects of electron screening on ECs are ignored. Screening lowers EC rates and thus leads to a higher electron fraction. We implement electron screening on ECs to calculate explosive SN Ia nucleosynthesis in a near-M_Ch single degenerate model. It is found that some of neutron-rich nuclear abundances, namely those of 46,48Ca, 50Ti, 54Cr, 58Fe, 64Ni and 67,70Zn, decrease when screening effects on ECs are considered. Of these, 50Ti, 54Cr and 58Fe are particularly interesting because a significant portion of the solar abundance of these nuclei is presumed to originate from SNe Ia. We conclude that implementing the screening effect on ECs in modern SN Ia models is desirable to precisely calculate abundances of neutron-rich nuclides.

arXiv comment7 pages, 7 figures, accepted for publication in ApJ

References in corpus (34)

• Nucleosynthesis in Chandrasekhar Mass Models for Type Ia Supernovae and Constraints on Progenitor Systems and Burning-Front Propagation
• The Shell Model as Unified View of Nuclear Structure
• Three-dimensional delayed-detonation models with nucleosynthesis for Type Ia supernovae
• Nearby Supernova Rates from the Lick Observatory Supernova Search. III. The Rate-Size Relation, and the Rates as a Function of Galaxy Hubble Type and Colour
• New effective interaction for $pf$-shell nuclei and its implications for the stability of the $N$=$Z$=28 closed core
• Surface Detonations in Double Degenerate Binary Systems Triggered by Accretion Stream Instabilities
• The Role of Electron Captures in Chandrasekhar Mass Models for Type Ia Supernovae
• Nucleosynthesis in Two-Dimensional Delayed Detonation Models of Type Ia Supernova Explosions
• Improved estimate of electron capture rates on nuclei during stellar core collapse
• Explosive Nucleosynthesis in Near-Chandrasekhar Mass White Dwarf Models for Type Ia Supernovae: Dependence on Model Parameters
• A Chandrasekhar Mass Progenitor for the Type Ia Supernova Remnant 3C 397 from The Enhanced Abundances of Nickel and Manganese
• Can Deflagration-Detonation-Transitions occur in Type Ia Supernovae?
• New Evidence for Efficient Collisionless Heating of Electrons at the Reverse Shock of a Young Supernova Remnant
• Late-time supernova light curves: The effect of internal conversion and Auger electrons
• Electron capture and beta-decay rates for sd-shell nuclei in stellar environments relevant to high density O-Ne-Mg cores
• Electron capture on iron group nuclei
• Late-Time Photometry of Type Ia Supernova SN 2012cg Reveals the Radioactive Decay of ${}^{57}$Co
• Screening Corrections to the Electron Capture Rates in Dense Stars by the Relativistically Degenerate Electron Liquid
• Whimper of a Bang: Documenting the Final Days of the Nearby Type Ia Supernova 2011fe
• The late-time light curve of the type Ia supernova SN 2011fe
• Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Deflagration to Detonation Density
• The Effects of Variations in Nuclear Interactions on Nucleosynthesis in Thermonuclear Supernovae
• A Super-Solar Metallicity for the Progenitor of Kepler's Supernova
• Impact of New Gamow-Teller Strengths on Explosive Type Ia Supernova Nucleosynthesis
• Late-time Flattening of Type Ia Supernova Light Curves: Constraints From SN 2014J in M82
• Nucleosynthesis Constraints on the Explosion Mechanism for Type Ia Supernovae
• Evaluating Systematic Dependencies of Type Ia Supernovae: The Influence of Central Density
• Observations of SN 2015F suggest a correlation between the intrinsic luminosity of Type Ia supernovae and the shape of their light curves >900 days after explosion
• Constraining Type Ia Supernova Progenitor Scenarios with Extremely Late-time Photometry of Supernova SN 2013aa
• Sensitivity of Type Ia supernovae to electron capture rates
• Low-lying Resonances and Relativistic Screening in Big Bang Nucleosynthesis
• Nuclear Reaction Screening, Weak Interactions, and r-Process Nucleosynthesis in High Magnetic Fields
• Observations of Type Ia Supernova 2014J for Nearly 900 Days and Constraints on Its Progenitor System
• Screening corrections to Electron Capture Rates and resulting constraints on Primordial Magnetic Fields

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