Quantifying how density gradients and front curvature affect carbon detonation strength during SNe Ia

Broxton J. Miles, Dean M. Townsley, Ken J. Shen, Francis Timmes, Kevin Moore

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Accurately reproducing the physics behind the detonations of SNe Ia and the resultant nucleosynthetic yields is important for interpreting observations of spectra and remnants. The scales of the processes involved span orders of magnitudes, making the problem computationally impossible to ever fully resolve in full-star simulations in the present and near future. In the lower density regions of the star, the curvature of the detonation front will slow the detonation, affecting the production of intermediate mass elements. We find that shock strengthening due to the density gradient present in the outer layers of the progenitor is essential for understanding the nucleosynthesis there, with burning extending well below the density at which a steady-state detonation is extinct. We show that a complete reaction network is not sufficient to obtain physical detonations at high densities and modest resolution due to numerical mixing at the unresolved reaction front. At low densities, below 6 × 10 5 g cm -3 , it is possible to achieve high enough resolution to separate the shock and the reaction region, and the abundance structure predicted by fully resolved quasi-steady-state calculations is obtained. For our best current benchmark yields, we utilize a method in which the unresolved portion of Lagrangian histories are reconstructed based on fully resolved quasi-steady-state detonation calculations. These computations demonstrate that under-resolved simulations agree approximately, ∼10% in post-shock values of temperature, pressure, density, and abundances, with expected detonation structures sufficiently far from the under-resolved region, but that there is still room for some improvement in the treatment of subgrid reactions in the hydrodynamics to before better than 1% can be achieved at all densities.

Original languageEnglish (US)
Article number154
JournalAstrophysical Journal
Volume871
Issue number2
DOIs
StatePublished - Feb 1 2019

Fingerprint

detonation
curvature
gradients
carbon
quasi-steady states
shock
stars
nuclear fusion
rooms
simulation
physics
hydrodynamics
histories
high resolution
history
temperature

Keywords

  • methods: Numerical
  • nuclear reactions, nucleosynthesis, abundances
  • shock waves
  • supernovae: General

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Quantifying how density gradients and front curvature affect carbon detonation strength during SNe Ia. / Miles, Broxton J.; Townsley, Dean M.; Shen, Ken J.; Timmes, Francis; Moore, Kevin.

In: Astrophysical Journal, Vol. 871, No. 2, 154, 01.02.2019.

Research output: Contribution to journalArticle

Miles, Broxton J. ; Townsley, Dean M. ; Shen, Ken J. ; Timmes, Francis ; Moore, Kevin. / Quantifying how density gradients and front curvature affect carbon detonation strength during SNe Ia. In: Astrophysical Journal. 2019 ; Vol. 871, No. 2.
@article{540d2fa5a3ef43e5861cc9e19b577ee1,
title = "Quantifying how density gradients and front curvature affect carbon detonation strength during SNe Ia",
abstract = "Accurately reproducing the physics behind the detonations of SNe Ia and the resultant nucleosynthetic yields is important for interpreting observations of spectra and remnants. The scales of the processes involved span orders of magnitudes, making the problem computationally impossible to ever fully resolve in full-star simulations in the present and near future. In the lower density regions of the star, the curvature of the detonation front will slow the detonation, affecting the production of intermediate mass elements. We find that shock strengthening due to the density gradient present in the outer layers of the progenitor is essential for understanding the nucleosynthesis there, with burning extending well below the density at which a steady-state detonation is extinct. We show that a complete reaction network is not sufficient to obtain physical detonations at high densities and modest resolution due to numerical mixing at the unresolved reaction front. At low densities, below 6 × 10 5 g cm -3 , it is possible to achieve high enough resolution to separate the shock and the reaction region, and the abundance structure predicted by fully resolved quasi-steady-state calculations is obtained. For our best current benchmark yields, we utilize a method in which the unresolved portion of Lagrangian histories are reconstructed based on fully resolved quasi-steady-state detonation calculations. These computations demonstrate that under-resolved simulations agree approximately, ∼10{\%} in post-shock values of temperature, pressure, density, and abundances, with expected detonation structures sufficiently far from the under-resolved region, but that there is still room for some improvement in the treatment of subgrid reactions in the hydrodynamics to before better than 1{\%} can be achieved at all densities.",
keywords = "methods: Numerical, nuclear reactions, nucleosynthesis, abundances, shock waves, supernovae: General",
author = "Miles, {Broxton J.} and Townsley, {Dean M.} and Shen, {Ken J.} and Francis Timmes and Kevin Moore",
year = "2019",
month = "2",
day = "1",
doi = "10.3847/1538-4357/aaf8a5",
language = "English (US)",
volume = "871",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "2",

}

TY - JOUR

T1 - Quantifying how density gradients and front curvature affect carbon detonation strength during SNe Ia

AU - Miles, Broxton J.

AU - Townsley, Dean M.

AU - Shen, Ken J.

AU - Timmes, Francis

AU - Moore, Kevin

PY - 2019/2/1

Y1 - 2019/2/1

N2 - Accurately reproducing the physics behind the detonations of SNe Ia and the resultant nucleosynthetic yields is important for interpreting observations of spectra and remnants. The scales of the processes involved span orders of magnitudes, making the problem computationally impossible to ever fully resolve in full-star simulations in the present and near future. In the lower density regions of the star, the curvature of the detonation front will slow the detonation, affecting the production of intermediate mass elements. We find that shock strengthening due to the density gradient present in the outer layers of the progenitor is essential for understanding the nucleosynthesis there, with burning extending well below the density at which a steady-state detonation is extinct. We show that a complete reaction network is not sufficient to obtain physical detonations at high densities and modest resolution due to numerical mixing at the unresolved reaction front. At low densities, below 6 × 10 5 g cm -3 , it is possible to achieve high enough resolution to separate the shock and the reaction region, and the abundance structure predicted by fully resolved quasi-steady-state calculations is obtained. For our best current benchmark yields, we utilize a method in which the unresolved portion of Lagrangian histories are reconstructed based on fully resolved quasi-steady-state detonation calculations. These computations demonstrate that under-resolved simulations agree approximately, ∼10% in post-shock values of temperature, pressure, density, and abundances, with expected detonation structures sufficiently far from the under-resolved region, but that there is still room for some improvement in the treatment of subgrid reactions in the hydrodynamics to before better than 1% can be achieved at all densities.

AB - Accurately reproducing the physics behind the detonations of SNe Ia and the resultant nucleosynthetic yields is important for interpreting observations of spectra and remnants. The scales of the processes involved span orders of magnitudes, making the problem computationally impossible to ever fully resolve in full-star simulations in the present and near future. In the lower density regions of the star, the curvature of the detonation front will slow the detonation, affecting the production of intermediate mass elements. We find that shock strengthening due to the density gradient present in the outer layers of the progenitor is essential for understanding the nucleosynthesis there, with burning extending well below the density at which a steady-state detonation is extinct. We show that a complete reaction network is not sufficient to obtain physical detonations at high densities and modest resolution due to numerical mixing at the unresolved reaction front. At low densities, below 6 × 10 5 g cm -3 , it is possible to achieve high enough resolution to separate the shock and the reaction region, and the abundance structure predicted by fully resolved quasi-steady-state calculations is obtained. For our best current benchmark yields, we utilize a method in which the unresolved portion of Lagrangian histories are reconstructed based on fully resolved quasi-steady-state detonation calculations. These computations demonstrate that under-resolved simulations agree approximately, ∼10% in post-shock values of temperature, pressure, density, and abundances, with expected detonation structures sufficiently far from the under-resolved region, but that there is still room for some improvement in the treatment of subgrid reactions in the hydrodynamics to before better than 1% can be achieved at all densities.

KW - methods: Numerical

KW - nuclear reactions, nucleosynthesis, abundances

KW - shock waves

KW - supernovae: General

UR - http://www.scopus.com/inward/record.url?scp=85062035227&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85062035227&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/aaf8a5

DO - 10.3847/1538-4357/aaf8a5

M3 - Article

AN - SCOPUS:85062035227

VL - 871

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 154

ER -