Accretion-Induced Collapse of Old White Dwarfs

1987 ◽  
Vol 93 ◽  
pp. 665-669
Author(s):  
J. Isern ◽  
R. Canal ◽  
M. Hernanz ◽  
J. Labay
Keyword(s):  
Neutron Stars ◽  
Gravitational Collapse ◽  
White Dwarfs ◽  
Binary Systems ◽  
Observational Evidence ◽  
Dynamical Instability ◽  
Thermonuclear Explosion

AbstractThere is observational evidence of the presence of young neutron stars in old binary systems. A likely explanation is that those neutron stars were produced in the collapse of old CO white dwarfs. We show how mass accretion on initially solid white dwarfs can leave central solid cores when dynamical instability sets in and we study the different effects of the existence of such cores on the outcome of the competition between thermonuclear explosion and gravitational collapse.

scholarly journals Gravitational Collapse of Mass-Accreting White Dwarfs

1989 ◽  
Vol 114 ◽  
pp. 88-91
Author(s):  
J. Isern ◽  
R. Canal ◽  
D. García ◽  
M. Hernanz ◽  
J. Labay
Keyword(s):  
Neutron Stars ◽  
Gravitational Collapse ◽  
Binary Systems ◽  
Massive Star ◽  
Dynamical Instability ◽  
Core Collapse ◽  
Type I ◽  
Radio Pulsars ◽  
X Ray ◽  
Different Types

Massive star (M ≥ 10 M ) core collapse is the standard mechanism for neutron star formation (see Brown 1988 for a recent review). It has long been realized (see, for instance, van den Heuvel 1988, and references therein) that the neutron stars found in different types of binary systems cannot come from such a standard mechanism. Those systems include wide binary radio pulsars, millisecond pulsars (not in wide binaries), galactic bulge X–ray sources (including QPO’s), type I X–ray burst sources and X–ray transients, andγ–ray sources. Formation of those neutron stars is now widely attributed to the gravitational collapse of a white dwarf, growing above Chandrasekhar’s limit by mass accretion from the current neutron star’s companion in the binary system (Canal and Schatzman 1976; Canal and Isern 1979; Canal, Isern, and Labay 1980; Miyaji et al. 1980). Mass growth up to dynamical instability means that both explosive ejection of the accreted layers and explosive disruption of the whole star must be avoided. The former is associated with the nova phenomenon. The latter, with the occurrence of type I supernovae.

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 Neutron Star Formation in Theoretical Supernovae — Low Mass Stars and White Dwarfs —

1987 ◽  
Vol 125 ◽  
pp. 281-303
Author(s):  
Ken'ichi Nomoto
Keyword(s):  
Neutron Stars ◽  
White Dwarfs ◽  
Binary Systems ◽  
Crab Nebula ◽  
Close Binary ◽  
Low Mass Stars ◽  
Supernova Explosions ◽  
Low Mass ◽  
Strongly Degenerate ◽  
The Crab Nebula

The presupernova evolution of stars that form semi-degenerate or strongly degenerate O+Ne+Mg cores is discussed. For the 10–13 M⊙ stars, behavior of off-center neon flashes is crucial. The 8–10 M⊙ stars do not ignite neon and eventually collapse due to electron captures. Properties of supernova explosions and neutron stars expected from these low mass progenitors are compared with the Crab nebula. We also examine the conditions for which neutron stars form from accretion-induced collapse of white dwarfs in close binary systems.

scholarly journals Existence of Chandrasekhar’s limit in generalized uncertainty white dwarfs

2021 ◽  
Vol 8 (6) ◽  
pp. 210301
Author(s):  
Arun Mathew ◽  
Malay K. Nandy
Keyword(s):  
General Relativity ◽  
Stability Analysis ◽  
Gravitational Collapse ◽  
White Dwarfs ◽  
Generalized Uncertainty Principle ◽  
Compact Objects ◽  
Dynamical Instability ◽  
Astronomical Observations ◽  
Theoretical Investigations ◽  
Chandrasekhar Limit

The existence of Chandrasekhar’s limit has played various decisive roles in astronomical observations for many decades. However, various recent theoretical investigations suggest that gravitational collapse of white dwarfs is withheld for arbitrarily high masses beyond Chandrasekhar’s limit if the equation of state incorporates the effect of quantum gravity via the generalized uncertainty principle. There have been a few attempts to restore the Chandrasekhar limit but they are found to be inadequate. In this paper, we rigorously resolve this problem by analysing the dynamical instability in general relativity. We confirm the existence of Chandrasekhar’s limit as well as stable mass–radius curves that behave consistently with astronomical observations. Moreover, this stability analysis suggests gravitational collapse beyond the Chandrasekhar limit signifying the possibility of compact objects denser than white dwarfs.

scholarly journals Deriving fundamental parameters of millisecond pulsars via AIC in white dwarfs

2012 ◽  
Vol 8 (S290) ◽  
pp. 177-178
Author(s):  
A. Taani ◽  
C. M. Zhang ◽  
Y. H. Zhao ◽  
A. Moraghan
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
White Dwarfs ◽  
Binary Systems ◽  
Millisecond Pulsars ◽  
Fundamental Parameters ◽  
Evolutionary Connection ◽  
Binary Evolution

AbstractWe present a study of the observational properties of Millisecond Pulsars (MSPs) by way of their magnetic fields, spin periods and masses. These measurements are derived through the scenario of Accretion Induced Collapse (AIC) of white dwarfs (WDs) in stellar binary systems, in order to provide a greater understanding of the characteristics of MSP populations. In addition, we demonstrate a strong evolutionary connection between neutron stars and WDs with binary companions from a stellar binary evolution perspective via the AIC process.

scholarly journals On the Origin of Neutron Stars in Globular Clusters

1987 ◽  
Vol 125 ◽  
pp. 173-185
Author(s):  
Jonathan E. Grindlay
Keyword(s):  
Neutron Stars ◽  
Globular Clusters ◽  
White Dwarfs ◽  
Binary Systems ◽  
High Luminosity ◽  
X Ray ◽  
Origin And Evolution ◽  
Compact Binary ◽  
X Ray Binaries ◽  
Mass Functions

The formation of neutron stars in globular clusters is discussed in light of a number of recent results and, in particular, studies of the origin and evolution of the high luminosity x-ray binaries found in globular clusters. We argue that the neutron stars most probably arise from the accretion-induced collapse of white dwarfs in compact binary systems, themselves detectable as low luminosity cluster x-ray sources. The white dwarfs which can collapse are probably the remnants of relatively more massive stars than those presently found in globulars. This can account for the predominant occurrence of the high luminosity cluster sources in clusters of relatively high metallicity, since those clusters have recently been found to probably have flatter mass functions of their component stars.

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 Magnetic field amplification in newly-born neutron stars

1996 ◽  
Vol 160 ◽  
pp. 435-436
Author(s):  
H.-J. Wiebicke ◽  
U. Geppert
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Gravitational Collapse ◽  
Dipole Field ◽  
Numerical Calculations ◽  
Selection Effects ◽  
Thermoelectric Effects ◽  
Field Amplification ◽  
Seed Field ◽  
Flux Conservation

AbstractWe present a scenario of magnetic field (MF) evolution of newly-born neutron stars (NSs). Numerical calculations show that in the hot phase of young NSs the MF can be amplified by thermoelectric effects, starting from a moderately strong seed-field. Therefore, there is no need to assume a 1012G dipole field immediately after the gravitational collapse of the supernova (SN) event. The widely accepted scenario for such a field to be produced by flux conservation during the collapse is critically discussed. Instead, it can be generated by amplification and selection effects in the first 104yrs, and by the subsequent fast ohmic decay of higher multipole components, when the NS cools down.

Origin of Magnetic Fields in White Dwarfs and Neutron Stars

1971 ◽  
Vol 231 (19) ◽  
pp. 32-33 ◽  
Author(s):  
R. F. O'CONNELL ◽  
K. M. ROUSSEL
Keyword(s):  
Magnetic Fields ◽  
Neutron Stars ◽  
White Dwarfs
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