scholarly journals Type Ia supernovae deflagration-to-detonation transition explosions powered by the Zel’dovich reactivity gradient mechanism

2020 ◽  
Vol 501 (1) ◽  
pp. L23-L27
Author(s):  
E Brooker ◽  
T Plewa ◽  
D Fenn
Keyword(s):  
White Dwarf ◽  
Turbulence Models ◽  
Compressible Turbulence ◽  
Type Ia Supernovae ◽  
Deflagration To Detonation Transition ◽  
Weakly Compressible ◽  
Type Ia ◽  
Nuclear Burning ◽  
Detonation Transition ◽  
Ia Supernovae

ABSTRACT Our aim in this work is to identify and explain the necessary conditions required for an energetic explosion of a Chandrasekhar-mass white dwarf. We construct and analyse weakly compressible turbulence models with nuclear burning effects for carbon/oxygen plasma at a density expected for the deflagration-to-detonation transition (DDT) to occur. We observe the formation of carbon deflagrations and transient carbon detonations at early times. As turbulence becomes increasingly inhomogeneous, sustained carbon detonations are initiated by the Zel’dovich reactivity gradient mechanism. The fuel is suitably preconditioned by the action of compressive turbulent modes with wavelength comparable to the size of resolved turbulent eddies; no acoustic wave is involved in this process. Oxygen detonations are initiated, aided either by reactivity gradients or by collisions of carbon detonations. The observed evolutionary time-scales are found to be sufficiently short for the above process to occur in the expanding, centrally ignited massive white dwarf. The inhomogeneous conditions produced prior to the DDT might be of consequence for the chemical composition of the outer ejecta regions of Type Ia supernovae from the single degenerate channel, and offer the potential for validation of the proposed model.

scholarly journals SN 2011fe: A Laboratory for Testing Models of Type Ia Supernovae

2013 ◽  
Vol 30 ◽  
Author(s):  
Laura Chomiuk
Keyword(s):  
White Dwarf ◽  
Type Ia Supernovae ◽  
Companion Star ◽  
Excellent Opportunity ◽  
Type Ia ◽  
Multi Wavelength ◽  
Detonation Transition ◽  
Ia Supernovae ◽  
Minimal Evidence ◽  
Key Questions

AbstractSN 2011fe is the nearest supernova of Type Ia (SN Ia) discovered in the modern multi-wavelength telescope era, and it also represents the earliest discovery of an SN Ia to date. As a normal SN Ia, SN 2011fe provides an excellent opportunity to decipher long-standing puzzles about the nature of SNe Ia. In this review, we summarise the extensive suite of panchromatic data on SN 2011fe and gather interpretations of these data to answer four key questions: (1) What explodes in an SN Ia? (2) How does it explode? (3) What is the progenitor of SN 2011fe? and (4) How accurate are SNe Ia as standardisable candles? Most aspects of SN 2011fe are consistent with the canonical picture of a massive CO white dwarf undergoing a deflagration-to-detonation transition. However, there is minimal evidence for a non-degenerate companion star, so SN 2011fe may have marked the merger of two white dwarfs.

scholarly journals Ultra-soft Sources as Type Ia Supernovae Progenitors

2011 ◽  
Vol 7 (S281) ◽  
pp. 136-139
Author(s):  
Kelly Lepo ◽  
Marten van Kerkwijk
Keyword(s):  
White Dwarf ◽  
Planetary Nebula ◽  
Type Ia Supernovae ◽  
Transfer Rates ◽  
Upper Limit ◽  
Processed Material ◽  
Null Result ◽  
Type Ia ◽  
Nuclear Burning ◽  
Ia Supernovae

AbstractMissing from the usual considerations of nuclear burning white dwarfs as Type Ia supernovae progenitors are systems with very higher mass transfer rates, where more material than is needed for steady burning accretes on the white dwarf. This will expand the photosphere of the white dwarf, causing it to emit at longer wavelengths. Thus, we propose the name ultra-soft source (USS) for these objects.We present a VLT/FLAMES survey looking for USSs in the SMC, selected to be bright in the far UV and with blue far UV-V colors. While we find some unusual objects, and recover known planetary nebulae and WR stars, we detect no objects with strong He II lines, which should be a signature of USSs. This null result either puts an upper limit on the number of USSs in the SMC, or shows that we do not understand what the optical spectra of such objects will look like.We also discuss the unusual LMC [WN] planetary nebula LMC N66 as a possible example of a USS. It has a luminosity consistent with that expected, and its spectra show incompletely CNO-processed material — strong helium lines, some hydrogen, enhanced nitrogen and depleted carbon. It also shows periodic outbursts. USSs may resemble N66 in quiescence. However, it lacks a FUV excess, contrary to our predictions.

scholarly journals A unified mechanism for unconfined deflagration-to-detonation transition in terrestrial chemical systems and type Ia supernovae

Science ◽  
2019 ◽  
Vol 366 (6465) ◽  
pp. eaau7365 ◽  
Author(s):  
Alexei Y. Poludnenko ◽  
Jessica Chambers ◽  
Kareem Ahmed ◽  
Vadim N. Gamezo ◽  
Brian D. Taylor
Keyword(s):  
Theoretical Models ◽  
Type Ia Supernovae ◽  
Dwarf Stars ◽  
Chemical Systems ◽  
White Dwarf Stars ◽  
Deflagration To Detonation Transition ◽  
Type Ia ◽  
Detonation Transition ◽  
Ia Supernovae ◽  
Open Question

The nature of type Ia supernovae (SNIa)—thermonuclear explosions of white dwarf stars—is an open question in astrophysics. Virtually all existing theoretical models of normal, bright SNIa require the explosion to produce a detonation in order to consume all of stellar material, but the mechanism for the deflagration-to-detonation transition (DDT) remains unclear. We present a unified theory of turbulence-induced DDT that describes the mechanism and conditions for initiating detonation both in unconfined chemical and thermonuclear explosions. The model is validated by using experiments with chemical flames and numerical simulations of thermonuclear flames. We use the developed theory to determine criteria for detonation initiation in the single-degenerate Chandrasekhar-mass SNIa model and show that DDT is almost inevitable at densities of 107 to 108 grams per cubic centimeter.

scholarly journals Neutrinos from type Ia supernovae: The deflagration-to-detonation transition scenario

2016 ◽  
Vol 94 (2) ◽  
Author(s):  
Warren P. Wright ◽  
Gautam Nagaraj ◽  
James P. Kneller ◽  
Kate Scholberg ◽  
Ivo R. Seitenzahl
Keyword(s):  
Type Ia Supernovae ◽  
Deflagration To Detonation Transition ◽  
Type Ia ◽  
Detonation Transition ◽  
Ia Supernovae ◽  
Transition Scenario

scholarly journals Are the Precursors of Type Ia Supernovae Double Degenerate Mergers?

2004 ◽  
Vol 194 ◽  
pp. 111-112
Author(s):  
Lilia Ferrario
Keyword(s):  
Neutron Stars ◽  
White Dwarf ◽  
White Dwarfs ◽  
Observational Evidence ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae

AbstractI argue that the observational evidence for white dwarf-white dwarf mergers supports the view that they give rise to ultra-massive white dwarfs or neutron stars through accretion induced collapse. The implications for the progenitors of Type Ia SNe are discussed.

scholarly journals Symbiotic Stars as Possible Progenitors of SNe Ia: Binary Parameters and Overall Outlook

2011 ◽  
Vol 7 (S281) ◽  
pp. 162-165 ◽  
Author(s):  
J. Mikołajewska
Keyword(s):  
White Dwarf ◽  
Physical Characteristics ◽  
Type Ia Supernovae ◽  
Symbiotic Stars ◽  
Type Ia ◽  
Red Giant ◽  
Ia Supernovae

AbstractSymbiotic stars are interacting binaries in which the first-formed white dwarf accretes and burns material from a red giant companion. This paper aims at presenting physical characteristics of these objects and discussing their possible link with progenitors of Type Ia supernovae.

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