scholarly journals Sensitivity of Type Ia supernovae to electron capture rates

2019 ◽  
Vol 624 ◽  
pp. A139 ◽  
Author(s):  
E. Bravo
Keyword(s):  
Weak Interactions ◽  
Dynamical Evolution ◽  
Sensitivity Study ◽  
Decay Rates ◽  
Type Ia Supernovae ◽  
Thermonuclear Explosion ◽  
Type Ia ◽  
Long Time ◽  
Ia Supernovae ◽  
The Impact

The thermonuclear explosion of massive white dwarfs is believed to explain at least a fraction of Type Ia supernovae (SNIa). After thermal runaway, electron captures on the ashes left behind by the burning front determine a loss of pressure, which impacts the dynamics of the explosion and the neutron excess of matter. Indeed, overproduction of neutron-rich species such as 54Cr has been deemed a problem of Chandrasekhar-mass models of SNIa for a long time. I present the results of a sensitivity study of SNIa models to the rates of weak interactions, which have been incorporated directly into the hydrodynamic explosion code. The weak rates have been scaled up or down by a factor ten, either globally for a common bibliographical source, or individually for selected isotopes. In line with previous works, the impact of weak rates uncertainties on sub-Chandrasekhar models of SNIa is almost negligible. The impact on the dynamics of Chandrasekhar-mass models and on the yield of 56Ni is also scarce. The strongest effect is found on the nucleosynthesis of neutron-rich nuclei, such as 48Ca, 54Cr, 58Fe, and 64Ni. The species with the highest influence on nucleosynthesis do not coincide with the isotopes that contribute most to the neutronization of matter. Among the latter, there are protons, 54, 55Fe, 55Co, and 56Ni, while the main influencers are 54, 55Mn and 55 − 57Fe, in disagreement with Parikh et al (2013, A&A, 557, A3), who found that SNIa nucleosynthesis is most sensitive to the β+-decay rates of 28Si, 32S, and 36Ar. An increase in all weak rates on pf-shell nuclei would affect the dynamical evolution of burning bubbles at the beginning of the explosion and the yields of SNIa.

scholarly journals Gravitational Collapse versus Thermonuclear Explosion of Degenerate Stellar Cores

1994 ◽  
Vol 147 ◽  
pp. 186-213
Author(s):  
J. Isern ◽  
R. Canal
Keyword(s):  
Neutron Star ◽  
White Dwarfs ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Radioactive Elements ◽  
Border Line ◽  
Thermonuclear Explosion ◽  
Type Ia ◽  
Γ Rays ◽  
Ia Supernovae

AbstractIn this paper we review the behavior of growing stellar degenerate cores. It is shown that ONeMg white dwarfs and cold CO white dwarfs can collapse to form a neutron star. This collapse is completely silent since the total amount of radioactive elements that are expelled is very small and a burst of γ-rays is never produced. In the case of an explosion (always carbonoxygen cores), the outcome fits quite well the observed properties of Type Ia supernovae. Nevertheless, the light curves and the velocities measured at maximum are very homogeneous and the diversity introduced by igniting at different densities is not enough to account for the most extreme cases observed. It is also shown that a promising way out of this problem could be the He-induced detonation of white dwarfs with different masses. Finally, we outline that the location of the border line which separetes explosion from collapse strongly depends on the input physics adopted.

scholarly journals Type IA Supernovae

1992 ◽  
Vol 151 ◽  
pp. 225-234
Author(s):  
J. Craig Wheeler
Keyword(s):  
White Dwarf ◽  
Cataclysmic Variables ◽  
Type Ia Supernovae ◽  
Low Velocity ◽  
Severe Problem ◽  
Transfer Rates ◽  
Secular Evolution ◽  
Thermonuclear Explosion ◽  
Type Ia ◽  
Ia Supernovae

Spectral calculations show that a model based on the thermonuclear explosion of a degenerate carbon/oxygen white dwarf provides excellent agreement with observations of Type Ia supernovae. Identification of suitable evolutionary progenitors remains a severe problem. General problems with estimation of supernova rates are outlined and the origin of Type Ia supernovae from double degenerate systems are discussed in the context of new rates of explosion per H band luminosity, the lack of observed candidates, and the likely presence of H in the vicinity of some SN Ia events. Re-examination of the problems of triggering Type Ia by accretion of hydrogen from a companion shows that there may be an avenue involving cataclysmic variables, especially if extreme hibernation occurs. Novae may channel accreting white dwarfs to a unique locus in accretion rate/mass space. Systems that undergo secular evolution to higher mass transfer rates could lead to just the conditions necessary for a Type Ia explosion. Tests involving fluorescence or absorption in a surrounding circumstellar medium and the detection of hydrogen stripped from a companion, which should appear at low velocity inside the white dwarf ejecta, are suggested. Possible observational confirmation of the former is described.

scholarly journals Constraining spacetime variations of nuclear decay rates from light curves of type Ia supernovae

2015 ◽  
Vol 91 (12) ◽  
Author(s):  
Ivan Karpikov ◽  
Maxim Piskunov ◽  
Anton Sokolov ◽  
Sergey Troitsky
Keyword(s):  
Decay Rates ◽  
Light Curves ◽  
Type Ia Supernovae ◽  
Nuclear Decay ◽  
Type Ia ◽  
Ia Supernovae

scholarly journals A closer look at non-interacting He stars as a channel for producing the old population of type Ia supernovae

2020 ◽  
Vol 641 ◽  
pp. A20
Author(s):  
Zhengwei Liu ◽  
Richard J. Stancliffe
Keyword(s):  
Binary Systems ◽  
Type Ia Supernovae ◽  
Population Synthesis ◽  
Thermonuclear Explosion ◽  
Delay Times ◽  
Type Ia ◽  
Binary Evolution ◽  
Chandrasekhar Limit ◽  
Ia Supernovae ◽  
Almost All

The nature of the progenitors of type Ia supernovae (SNe Ia) remains a mystery. Binary systems consisting of a white dwarf (WD) and a main-sequence (MS) donor are potential progenitors of SNe Ia, in which a thermonuclear explosion of the WD may occur when its mass reaches the Chandrasekhar limit during accretion of material from a companion star. In the present work, we address theoretical rates and delay times of a specific MS donor channel to SNe Ia, in which a helium (He) star + MS binary produced from a common envelope event subsequently forms a WD + MS system without the He star undergoing mass transfer by Roche lobe overflow. By combining the results of self-consistent binary evolution calculations with population synthesis models, we find that the contribution of SNe Ia in this channel is around 2.0 × 10−4 yr−1. In addition, we find that delay times of SNe Ia in this channel cover a range of about 1.0–2.6 Gyr, and almost all SNe Ia produced in this way (about 97%) have a delay time of ≳1 Gyr. While the rate of SN Ia in this work is about 10% of the overall SN Ia rate, the channel represents a possible contribution to the old population (1–3 Gyr) of observed SNe Ia.

Overview of astroparticle physics and dark matter searches

2007 ◽  
Vol 22 (31) ◽  
pp. 5735-5746
Author(s):  
Nathalie Palanque-Delabrouille
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Acoustic Oscillation ◽  
Type Ia Supernovae ◽  
Clusters Of Galaxies ◽  
Astroparticle Physics ◽  
The Status ◽  
Type Ia ◽  
Ia Supernovae ◽  
The Impact

We present a general overview of recent results in the searches for dark matter and dark energy. We discuss the observation of the collision between two clusters of galaxies, and the impact this has on the relevance of dark matter. We then present the final results from microlensing experiments, which aimed at detecting dark baryonic objects in the halo of our galaxy, and the status of direct searches for WIMPs. We present the evidence for dark energy which initially comes from experiments dedicated to the study of distant type Ia supernovae. The measure of the baryon acoustic oscillation, an independent probe of the evolution of our universe that has recently brought interesting constraints, is finally described.

scholarly journals A Numerical Study of the Chemo-Dynamical Evolution of Elliptical Galaxies

2003 ◽  
Vol 208 ◽  
pp. 413-414
Author(s):  
Daisuke Kawata ◽  
Brad K. Gibson
Keyword(s):  
Chemical Elements ◽  
Numerical Study ◽  
Three Dimensional ◽  
Dynamical Evolution ◽  
Elliptical Galaxies ◽  
Type Ia Supernovae ◽  
Type Ii ◽  
End Products ◽  
Type Ia ◽  
Ia Supernovae

We investigate the chemo-dynamical evolution of elliptical galaxies, to understand the origin of the mass-dependence of photometric properties such as the colour-magnitude relation (CMR). Our three-dimensional TREE N-body/SPH numerical simulation takes into account both Type II and Type Ia supernovae and follows the evolution of the abundances of several chemical elements. We derive the photometric properties of the simulation end-products and compare them with the observed CMR.

scholarly journals Thermonuclear explosion of a massive hybrid HeCO white-dwarf triggered by a He-detonation on a companion

2021 ◽  
Author(s):  
R Pakmor ◽  
Y Zenati ◽  
H B Perets ◽  
S Toonen
Keyword(s):  
Stellar Evolution ◽  
Two Dimensions ◽  
Type Ia Supernovae ◽  
Normal Type ◽  
The Core ◽  
Thermonuclear Explosion ◽  
Self Consistent ◽  
Type Ia ◽  
Ia Supernovae ◽  
Secondary Carbon

Abstract Normal type Ia supernovae (SNe) are thought to arise from the thermonuclear explosion of massive (>0.8 M⊙) carbon-oxygen white dwarfs (WDs), although the exact mechanism is debated. In some models helium accretion on to a carbon-oxygen (CO) WD from a companion was suggested to dynamically trigger a detonation of the accreted helium shell. The helium detonation then produces a shock that after converging on itself close to the core of the CO-WD, triggers a secondary carbon detonation and gives rise to an energetic explosion. However, most studies of such scenarios have been done in one or two dimensions, and/or did not consider self-consistent models for the accretion and the He-donor. Here we make use of detailed 3D simulation to study the interaction of a He-rich hybrid 0.69 M⊙ HeCO WD with a more massive 0.8 M⊙ CO WD. We find that accretion from the hybrid WD on to the CO WD gives rise to a helium detonation. However, the helium detonation does not trigger a carbon detonation in the CO WD. Instead, the helium detonation burns through the accretion stream to also burn the helium shell of the donor hybrid HeCO-WD. The detonation of its massive helium shell then compresses its CO core, and triggers its detonation and full destruction. The explosion gives rise to a faint, likely highly reddened transient, potentially observable by the Vera Rubin survey, and the high-velocity (∼1000 kms−1) ejection of the heated surviving CO WD companion. Pending on uncertainties in stellar evolution we estimate the rate of such transient to be up to $\sim 10{{\ \rm per\ cent}}$ of the rate of type Ia SNe.

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