Contact interaction of surfaces under compression conditions

Most of the leading explosion scenarios for Type Ia supernovae involve the nuclear incineration of a white dwarf star through a detonation wave. Several scenarios have been proposed as to how this detonation may actually occur, but the exact mechanism and environment in which it takes place remain unknown. We explore the effects of an off-center initiated detonation on the spatial distribution of the nucleosynthetic yield products in a toy model -a pre-expanded near Chandrasekhar-mass white dwarf. We find that a single-point near edge-lit detonation results in asymmetries in the density and thermal profiles, notably the expansion timescale, throughout the supernova ejecta. We demonstrate that this asymmetry of the thermodynamic trajectories should be common to off-center detonations where a small amount of the star is burned prior to detonation. The sensitivity of the yields on the expansion timescale results in an asymmetric distribution of the elements synthesized as reaction products. We tabulate the shift in the center of mass of the various elements produced in our model supernova and find an odd-even pattern for elements past silicon. Our calculations show that off-center single-point detonations in carbon-oxygen white dwarfs are marked by significant composition asymmetries in their remnants which bear potentially observable signatures in both velocity and coordinate space, including an elemental nickel mass fraction which varies by a factor of two to three from one side of the remnant to the other.

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“…We find that nuclear burning in SNe Ia progresses in three distinct stages (Khokhlov 1983(Khokhlov , 1991. The first stage is carbon burning.…”

Section: Nucleosynthesis Dependencementioning

confidence: 81%

Asymmetry and the Nucleosynthetic Signature of Nearly Edge-Lit Detonation in White Dwarf Cores

Chamulak

Seitenzahl

Truran

2011

ApJ

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“…The burning of C and O under degenerate conditions can be described by three stages. First, C is consumed producing reaction products close to Mg. Then O is consumed along with the ashes of C burning, which produces a mixture of silicon group and light elements that is in a statistical quasi-equilibrium [59,60,61]. Finally the silicon-group nuclei are converted to IGEs, reaching full nuclear statistical equilibrium (NSE).…”

Section: Simulation Instrumentmentioning

confidence: 99%

Cosmic Chandlery with Thermonuclear Supernovae

Calder¹,

Krueger²,

Jackson³

et al. 2017

J. Phys.: Conf. Ser.

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Thermonuclear (Type Ia) supernovae are bright stellar explosions, the light curves of which can be calibrated to allow for use as "standard candles" for measuring cosmological distances. Contemporary research investigates how the brightness of an event may be influenced by properties of the progenitor system that follow from properties of the host galaxy such as composition and age. The goals are to better understand systematic effects and to assess the intrinsic scatter in the brightness, thereby reducing uncertainties in cosmological studies. We present the results from ensembles of simulations in the single-degenerate paradigm addressing the influence of age and metallicity on the brightness of an event and compare our results to observed variations of brightness that correlate with properties of the host galaxy. We also present results from "hybrid" progenitor models that incorporate recent advances in stellar evolution.

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“…The nuclear processing can be well-approximated as a three stage process: initially C is consumed, followed by O, which creates a mixture of Si group and light elements that is in quasi-statistical equilibrium, also known as nuclear statistical quasi-equilibrium (NSQE) [236][237][238][239][240]); finally the Si-group nuclei are converted to Fe group, reaching full nuclear statistical equilibrium, NSE. In both of these equilibrium states, the capture and creation of light elements (via photodisintegration) is balanced, so that energy release can continue by changing the relative abundance of light (low nuclear binding energy) and heavy (high nuclear binding energy) nuclides, an action that releases energy as buoyant burned material rises and expands.…”

Section: Flame Modelmentioning

confidence: 99%

The influence of chemical composition on models of Type Ia supernovae

et al. 2013

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Type Ia supernovae are bright stellar explosions distinguished by standardizable light curves that allow for their use as distance indicators for cosmological studies. Despite the highly successful use of these events in this capacity, many fundamental questions remain. Contemporary research investigates how properties of the progenitor system that follow from the host galaxy such as composition and age influence the brightness of an event with the goal of better understanding and assessing the intrinsic scatter in the brightness. We provide an overview of these supernovae and proposed progenitor systems, all of which involve one or more compact stars known as white dwarfs. We describe contemporary research investigating how the composition and structure of the progenitor white dwarf systematically influences the explosion outcome assuming the progenitor is a single white dwarf that has gained mass from a companion. We present results illustrating some of these systematic effects from our research.PACS numbers: 97.60. Bw,26.50.+x,97.20.Rp,95.30.Lz

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Contact interaction of surfaces under compression conditions

Cited by 3 publications

References 2 publications

Asymmetry and the Nucleosynthetic Signature of Nearly Edge-Lit Detonation in White Dwarf Cores

Asymmetry and the Nucleosynthetic Signature of Nearly Edge-Lit Detonation in White Dwarf Cores

Cosmic Chandlery with Thermonuclear Supernovae

The influence of chemical composition on models of Type Ia supernovae

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