Type Ia Supernova models arising from different distributions of igniting points

Garcı́a-Senz, Domingo; Bravo, Eduardo

doi:10.1051/0004-6361:20041628

Cited by 74 publications

(80 citation statements)

References 22 publications

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“…in García-Senz & Bravo (2005). At that time a DDT was artificially induced in the vicinity of the flame.…”

Section: Model Ddt3dbmentioning

confidence: 99%

A three-dimensional picture of the delayed-detonation model of type Ia supernovae

Bravo¹,

Garcı́a-Senz²

2007

A&A

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Aims. Deflagration models poorly explain the observed diversity of SNIa. Current multidimensional simulations of SNIa predict a significant amount of, so far unobserved, carbon and oxygen moving at low velocities. It has been proposed that these drawbacks can be resolved if there is a sudden jump to a detonation (delayed detonation), but these kinds of models have been explored mainly in one dimension. Here we present new three-dimensional delayed detonation models in which the deflagraton-to-detonation transition (DDT) takes place in conditions like those favored by one-dimensional models. Methods. We have used a smoothed-particle-hydrodynamics code adapted to follow all the dynamical phases of the explosion, with algorithms devised to handle subsonic as well as supersonic combustion fronts. The starting point was a centrally ignited C-O white dwarf of 1.38 M . When the average density on the flame surface reached ∼2−3 × 10 7 g cm −3 a detonation was launched. Results. The detonation wave processed more than 0.3 M of carbon and oxygen, emptying the central regions of the ejecta of unburned fuel and raising its kinetic energy close to the fiducial 10 51 erg expected from a healthy type Ia supernova. The final amount of 56 Ni synthesized also was in the correct range. However, the mass of carbon and oxygen ejected is still too high. Conclusions. The three-dimensional delayed detonation models explored here show an improvement over pure deflagration models, but they still fail to coincide with basic observational constraints. However, there are many aspects of the model that are still poorly known (geometry of flame ignition, mechanism of DDT, properties of detonation waves traversing a mixture of fuel and ashes). Therefore, it will be worth pursuing its exploration to see if a good SNIa model based on the three-dimensional delayed detonation scenario can be obtained.

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“…in García-Senz & Bravo (2005). At that time a DDT was artificially induced in the vicinity of the flame.…”

Section: Model Ddt3dbmentioning

confidence: 99%

A three-dimensional picture of the delayed-detonation model of type Ia supernovae

Bravo¹,

Garcı́a-Senz²

2007

A&A

Self Cite

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“…On the one hand, the conditions under which the thermonuclear runaway commences remain poorly understood so that the initial number and distribution of flamelets that seed the runaway is still a free parameter. On the other hand, although significant progress has been made in simulating flame fronts in multidimensional stellar models (see García-Senz & Bravo 2005;Gamezo et al 2005;Schmidt et al 2006b;Röpke et al 2007a;Townsley et al 2007;Jordan et al 2008, for recent examples from several groups), the challenge associated with modeling an unresolved turbulent deflagration (e.g., Schmidt et al 2006a) with limited computational resources injects an additional degree of uncertainty into the outcome of a model for any given choice of initial conditions. Readers are referred to Hillebrandt & Niemeyer (2000) for a review of the challenges associated with modeling and validating the SNe Ia explosion mechanism, and Röpke (2006) for an update on the state of multidimensional modeling.…”

Section: Introductionmentioning

confidence: 99%

STUDY OF THE DETONATION PHASE IN THE GRAVITATIONALLY CONFINED DETONATION MODEL OF TYPE Ia SUPERNOVAE

Meakin

Seitenzahl

Townsley

et al. 2009

ApJ

100

118

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We study the gravitationally confined detonation (GCD) model of Type Ia supernovae (SNe Ia) through the detonation phase and into homologous expansion. In the GCD model, a detonation is triggered by the surface flow due to single-point, off-center flame ignition in carbon-oxygen white dwarfs (WDs). The simulations are unique in terms of the degree to which nonidealized physics is used to treat the reactive flow, including weak reaction rates and a time-dependent treatment of material in nuclear statistical equilibrium (NSE). Careful attention is paid to accurately calculating the final composition of material which is burned to NSE and frozen out in the rapid expansion following the passage of a detonation wave over the high-density core of the WD; and an efficient method for nucleosynthesis postprocessing is developed which obviates the need for costly network calculations along tracer particle thermodynamic trajectories. Observational diagnostics are presented for the explosion models, including abundance stratifications and integrated yields. We find that for all of the ignition conditions studied here a self-regulating process comprised of neutronization and stellar expansion results in final 56 Ni masses of ∼1.1 M . But, more energetic models result in larger total NSE and stable Fe-peak yields. The total yield of intermediate mass elements is ∼ 0.1 M and the explosion energies are all around 1.5 × 10 51 erg. The explosion models are briefly compared to the inferred properties of recent SN Ia observations. The potential for surface detonation models to produce lower-luminosity (lower 56 Ni mass) SNe is discussed.

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“…The mounting evidence for diversity among observed type Ia supernovae renders the quest for realistic modelling of the ignition process yet more topical (Benetti et al 2005;Leonard et al 2005;Stritzinger et al 2005). Substantial efforts have been made to analyse the effect of choosing different initial burning regions in simulations of thermonuclear supernovae (García-Senz & Bravo 2005;. The multi-point ignition scenarios which have recently been presented by suggest that the energy generation becomes maximal for about one hundred ignitions.…”

Section: Introductionmentioning

confidence: 99%

Thermonuclear supernova simulations with stochastic ignition

Schmidt

Niemeyer

2006

A&A

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We apply an ad hoc model for dynamical ignition in three-dimensional numerical simulations of thermonuclear supernovae assuming pure deflagrations. The model makes use of the statistical description of temperature fluctuations in the pre-supernova core proposed by , ApJ, 616, 1102. Randomness in time is implemented by means of a Poisson process. We are able to vary the explosion energy and nucleosynthesis depending on the free parameter of the model which controls the rapidity of the ignition process. However, beyond a certain threshold, the strength of the explosion saturates and the outcome appears to be robust with respect to the number of ignitions. In the most energetic explosions, we find about 0.75 M of iron group elements. Other than in simulations with simultaneous multi-spot ignition, the amount of unburned carbon and oxygen at radial velocities of a few 10 3 km s −1 tends to be reduced for an ever increasing number of ignition events and, accordingly, more pronounced layering results.

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Type Ia Supernova models arising from different distributions of igniting points

Cited by 74 publications

References 22 publications

A three-dimensional picture of the delayed-detonation model of type Ia supernovae

A three-dimensional picture of the delayed-detonation model of type Ia supernovae

STUDY OF THE DETONATION PHASE IN THE GRAVITATIONALLY CONFINED DETONATION MODEL OF TYPE Ia SUPERNOVAE

Thermonuclear supernova simulations with stochastic ignition

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