scholarly journals White dwarf accretion and type Ia supernovae

2012 ◽  
Vol 8 (S290) ◽  
pp. 117-120
Author(s):  
Z. Han ◽  
X. Chen
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Type Ia Supernovae ◽  
Lower Mass ◽  
Type Ia ◽  
Chandrasekhar Limit ◽  
Ia Supernovae

AbstractType Ia supernovae (SNe Ia) are believed to be thermonuclear explosions of carbon-oxygen white dwarfs at a mass close to the Chandrasekhar limit. However, a white dwarf at birth has a significantly lower mass and needs to accrete mass to grow to the limit for the explosion. Various progenitor models have been proposed and those models play an important role in our understanding of SNe Ia and cosmology.

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 Double White Dwarf Merger Rates

2011 ◽  
Vol 7 (S281) ◽  
pp. 223-224
Author(s):  
Silvia Toonen ◽  
Gijs Nelemans ◽  
Simon Portegies Zwart
Keyword(s):  
White Dwarf ◽  
Delay Time ◽  
Time Distribution ◽  
White Dwarfs ◽  
Type Ia Supernovae ◽  
Common Envelope ◽  
Cosmological Distance ◽  
Type Ia ◽  
Ia Supernovae

AbstractType Ia supernovae (SNe Ia) are very successfully used as standard candles on cosmological distance scales, but so far the nature of the progenitor(s) is unclear. A possible scenario for SNe Ia are merging carbon/oxygen white dwarfs with a combined mass exceeding the Chandrasekhar mass. We determine the theoretical rates and delay time distribution of these mergers for two different common envelope prescriptions and metallicities. The shape of the delay time distributions is rather insensitive to the assumptions. The normalization is a factor ~3–13 too low compared to observations.

scholarly journals The WD+He star binaries as the progenitors of type Ia supernovae

2017 ◽  
Vol 26 (1) ◽  
Author(s):  
Bo Wang ◽  
Dongdong Liu
Keyword(s):  
Parameter Space ◽  
Stellar Evolution ◽  
White Dwarfs ◽  
Type Ia Supernovae ◽  
Population Synthesis ◽  
Accretion Rates ◽  
Type Ia ◽  
Chandrasekhar Limit ◽  
Ia Supernovae ◽  
Modest Reduction

AbstractEmploying the MESA stellar evolution code, we computed He accretion onto carbon-oxygen white dwarfs (CO WDs).We found two possible outcomes for models in which the WD steadily grows in mass towards the Chandrasekhar limit. For relatively low He-accretion rates carbon ignition occurs in the center, leading to a type Ia supernova (SN Ia) explosion, whereas for relatively high accretion rates carbon is ignited off-center, probably leading to collapse. Thus the parameter space producing SNe Ia is reduced compared to what was assumed in earlier papers, in which the possibility of off-center ignition was ignored. We then applied these results in binary population synthesis modelling, finding a modest reduction in the expected birthrate of SNe Ia resulting from the WD+He star channel.

scholarly journals A Search for Type Ia Supernova Progenitors: the Central Stars of the Planetary Nebulae NGC 2392 and NGC 6026

2011 ◽  
Vol 7 (S281) ◽  
pp. 221-222
Author(s):  
A. Danehkar ◽  
D. J. Frew ◽  
O. De Marco ◽  
Q. A. Parker
Keyword(s):  
Orbital Period ◽  
White Dwarf ◽  
Total Mass ◽  
Close Binaries ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Chandrasekhar Limit ◽  
Ia Supernovae ◽  
Central Stars ◽  
Interesting System

AbstractWe use photoionization modeling to assess the binary nature of the central stars of NGC 2392 and NGC 6026. If they are close binaries, they are potential Type Ia supernovae (SNe Ia) progenitors if the total mass exceeds the Chandrasekhar limit. We show that the nucleus of NGC 2392 likely has a hot, massive (≃1 M⊙) white dwarf companion, and a total mass of ~1.6 M⊙, making it an especially interesting system. The binary mass in NGC 6026 is less, ~1.1 M⊙. Even though its orbital period is short, it is not considered to be an SNe~Ia progenitor.

scholarly journals Significantly super-Chandrasekhar mass-limit of white dwarfs in noncommutative geometry

2021 ◽  
Vol 30 (05) ◽  
pp. 2150034
Author(s):  
Surajit Kalita ◽  
Banibrata Mukhopadhyay ◽  
T. R. Govindarajan
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Compact Object ◽  
Type Ia Supernovae ◽  
Mass Limit ◽  
Fusion Reactions ◽  
Standard Candle ◽  
Type Ia ◽  
Nuclear Fusion Reactions ◽  
Ia Supernovae

Chandrasekhar made the startling discovery about nine decades back that the mass of compact object white dwarf has a limiting value once nuclear fusion reactions stop therein. This is the Chandrasekhar mass-limit, which is [Formula: see text] for a nonrotating non-magnetized white dwarf. On approaching this limiting mass, a white dwarf is believed to spark off with an explosion called type Ia supernova, which is considered to be a standard candle. However, observations of several over-luminous, peculiar type Ia supernovae indicate the Chandrasekhar mass-limit to be significantly larger. By considering noncommutativity among the components of position and momentum variables, hence uncertainty in their measurements, at the quantum scales, we show that the mass of white dwarfs could be significantly super-Chandrasekhar and thereby arrive at a new mass-limit [Formula: see text], explaining a possible origin of over-luminous peculiar type Ia supernovae. The idea of noncommutativity, apart from the Heisenberg’s uncertainty principle, is there for quite sometime, without any observational proof however. Our finding offers a plausible astrophysical evidence of noncommutativity, arguing for a possible second standard candle, which has many far-reaching implications.

scholarly journals Two delays in white dwarf evolution revealed by Gaia

2019 ◽  
Vol 15 (S357) ◽  
pp. 175-178
Author(s):  
Sihao Cheng
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
The Other ◽  
High Mass ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Two Delays ◽  
Binary Evolution ◽  
Ia Supernovae

AbstractBy comparing two age indicators of high-mass white dwarfs (WDs) derived from Gaia data, two discoveries have been made recently: one is the existence of a cooling anomaly that produces the Q branch structure on the Hertzsprung–Russell diagram, and the other is the existence of high-mass WDs as double-WD merger products. The former poses a challenge for WD cooling models, and the latter has implications on binary evolution and type-Ia supernovae.

scholarly journals Thermonuclear explosions of rapidly differentially rotating white dwarfs: Candidates for superluminous Type Ia supernovae?

2018 ◽  
Vol 618 ◽  
pp. A124 ◽  
Author(s):  
M. Fink ◽  
M. Kromer ◽  
W. Hillebrandt ◽  
F.K. Röpke ◽  
R. Pakmor ◽  
...  
Keyword(s):  
White Dwarfs ◽  
Three Dimensional ◽  
Radioactive Decay ◽  
Theoretical Explanation ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Chandrasekhar Limit ◽  
Ia Supernovae ◽  
First Time ◽  
Detonation Model

The observed sub-class of “superluminous” Type Ia supernovae lacks a convincing theoretical explanation. If the emission of such objects were powered exclusively by radioactive decay of 56Ni formed in the explosion, a progenitor mass close to or even above the Chandrasekhar limit for a non-rotating white dwarf star would be required. Masses significantly exceeding this limit can be supported by differential rotation. We, therefore, explore explosions and predict observables for various scenarios resulting from differentially rotating carbon–oxygen white dwarfs close to their respective limit of stability. Specifically, we have investigated a prompt detonation model, detonations following an initial deflagration phase (“delayed detonation” models), and a pure deflagration model. In postprocessing steps, we performed nucleosynthesis and three-dimensional radiative transfer calculations, that allow us, for the first time, to consistently derive synthetic observables from our models. We find that all explosion scenarios involving detonations produce very bright events. The observables predicted for them, however, are inconsistent with any known subclass of Type Ia supernovae. Pure deflagrations resemble 2002cx-like supernovae and may contribute to this class. We discuss implications of our findings for the explosion mechanism and for the existence of differentially rotating white dwarfs as supernova progenitors.

scholarly journals THE POST-MERGER MAGNETIZED EVOLUTION OF WHITE DWARF BINARIES: THE DOUBLE-DEGENERATE CHANNEL OF SUB-CHANDRASEKHAR TYPE Ia SUPERNOVAE AND THE FORMATION OF MAGNETIZED WHITE DWARFS

2013 ◽  
Vol 773 (2) ◽  
pp. 136 ◽  
Author(s):  
Suoqing Ji ◽  
Robert T. Fisher ◽  
Enrique García-Berro ◽  
Petros Tzeferacos ◽  
George Jordan ◽  
...  
Keyword(s):  
White Dwarf ◽  
White Dwarfs ◽  
Type Ia Supernovae ◽  
Type Ia ◽  
Ia Supernovae

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.

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