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Title: Realistic macronova models with detailed elemental opacities and thermalized r-process heating

Authors:
 [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340909
Report Number(s):
LA-UR-17-20220
DOE Contract Number:
AC52-06NA25396
Resource Type:
Conference
Resource Relation:
Conference: Neutron star mergers: From gravitational waves to nucleosynthesis ; 2017-01-15 - 2017-01-15 ; Hirschegg, Austria
Country of Publication:
United States
Language:
English
Subject:
radiative transfer, kilonova/macronova

Citation Formats

Wollaeger, Ryan Thomas. Realistic macronova models with detailed elemental opacities and thermalized r-process heating. United States: N. p., 2017. Web.
Wollaeger, Ryan Thomas. Realistic macronova models with detailed elemental opacities and thermalized r-process heating. United States.
Wollaeger, Ryan Thomas. Tue . "Realistic macronova models with detailed elemental opacities and thermalized r-process heating". United States. doi:. https://www.osti.gov/servlets/purl/1340909.
@article{osti_1340909,
title = {Realistic macronova models with detailed elemental opacities and thermalized r-process heating},
author = {Wollaeger, Ryan Thomas},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Jan 17 00:00:00 EST 2017},
month = {Tue Jan 17 00:00:00 EST 2017}
}

Conference:
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  • Almost half of heavy nuclei beyond iron are considered to be produced by rapid neutron capture process (r-process). This process occurs in the neutron-rich environment such as core-collapse supernovae or neutron star mergers, but the main production site is still unknown. In the r-process of neutron star mergers, nuclear fission reactions play an important role. Also beta-decay half-lives of magic nuclei are crucial for the r-process. We have carried out r-process nucleosynthesis calculations based upon new theoretical estimates of fission fragment distributions and new beta-decay half-lives for N=82 nuclei measured at RIBF-RIKEN. We investigate the effect of nuclear fission onmore » abundance patterns in the matter ejected from neutron star mergers with two different fission fragment mass distributions. We also discuss how the new experimental beta-decay half-lives affect the r-process.« less
  • A.N. Cox recently showed that a 20% opacity decrease in the 20,000--30,000 K region as indicated by the new Livermore OPAL opacities reconciles the discrepancy between pulsation and evolution masses of double-mode RR Lyrae variables. Nonlinear hydrodynamic calculations were performed for RR Lyrae models of mass 0l75 M{circle dot}, 51 L{circle dot}, and Z=0.0001 including this opacity decrease. The Stellingwerf periodic relaxation method was used to converge the models to a limit cycle, and the Floquet matrix eigenvalues calculated to search for a tendency of the fundamental mode to grow from the full-amplitude overtone solution, and the overtone mode tomore » grow from the full-amplitude fundamental solution, thereby predicting double-mode behavior. Models of T{sup eff} < 7000 K with the opacity decrease have positive fundamental-mode growth rates in the overtone solution, in contrast to earlier results by Hodson and Cox, and models with T{sub eff} < 7000 have positive 1st overtone growth rates in the fundamental-mode behavior was not found.« less
  • Cepheid models with enhanced opacity are constructed and used to determine pulsation constants, Q{sub 0}. These are compared to models without an enhanced opacity. Methods of determining Cepheid masses are investigated using the different models and are compared to results obtained by Gieren. The methods to determine the pulsation and Wesselink masses by ourselves and Gieren differ significantly, due to the use of a Q{sub 0} that varies with mass, radius and luminosity. 14 refs., 1 fig., 1 tab.