scholarly journals Low-energy core-collapse supernovae in the frame of the jittering jets explosion mechanism

2020 ◽  
Vol 494 (4) ◽  
pp. 5902-5908 ◽  
Author(s):  
Roni Anna Gofman ◽  
Noam Soker
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Binding Energy ◽  
Stellar Evolution ◽  
Low Energy ◽  
Core Collapse ◽  
Lower Range ◽  
Feedback Cycle ◽  
Explosion Mechanism ◽  
Stellar Masses

ABSTRACT We relate the pre-explosion binding energy of the ejecta of core-collapse supernovae (CCSNe) of stars with masses in the lower range of CCSNe and the location of the convection zones in the pre-collapse core of these stars, to explosion properties in the frame of the jittering jets explosion mechanism. Our main conclusion is that in the frame of the jittering jets explosion mechanism the remnant of a pulsar in these low-energy CCSNe has some significance, in that the launching of jets by the newly born neutron star (NS) spins-up the NS and create a pulsar. We crudely estimated the period of the pulsars to be tens of milliseconds in these cases. The convective zones seed perturbations that lead to accretion of stochastic angular momentum that in turn is assumed to launch jittering jets in this explosion mechanism. We calculate the binding energy and the location of the convective zones with the stellar evolution code mesa. For the lowest stellar masses, we study, MZAMS ≃ 8.5–11 M⊙, the binding energy above the convective zones is low, and so is the expected explosion energy in the jittering jets explosion mechanism that works in a negative feedback cycle. The expected mass of the NS remnant is MNS ≈ 1.25–1.6 M⊙, even for these low-energy CCSNe.

scholarly journals The Supernova/GRB Connection

2005 ◽  
Vol 192 ◽  
pp. 403-410 ◽  
Author(s):  
P. Höflich ◽  
D. Baade ◽  
A. Khokhlov ◽  
L. Wang ◽  
J.C. Wheeler
Keyword(s):  
Black Hole ◽  
Neutron Star ◽  
Central Region ◽  
Stellar Evolution ◽  
Axial Symmetry ◽  
Energy Deposition ◽  
Gamma Ray ◽  
Massive Stars ◽  
Core Collapse ◽  
Supernova Explosions

SummaryWe discuss the possible connection between supernova explosions (SN) and gamma-ray bursters (GRB) from the perspective of our current understanding of SN physics. Core collapse supernovae (SN) are the final stages of stellar evolution in massive stars during which the central region collapses, forms a neutron star (NS) or black hole, and the outer layers are ejected. Recent explosion scenarios assumed that the ejection is due to energy deposition by neutrinos into the envelope but detailed models do not produce powerful explosions. There is new and mounting evidence for an asphericity and, in particular, for axial symmetry in several supernovae which may be hard to reconcile within the spherical picture. The 3-D signatures are a key to understand core collapse supernovae and the GRB/SN connection. In this paper we study the effects and observational consequences of asymmetric explosions.

scholarly journals On the spin-up events and spin direction of the X-ray pulsar GX 301-2

2020 ◽  
Vol 496 (3) ◽  
pp. 3991-3995
Author(s):  
Jiren Liu
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Orbital Motion ◽  
Low Energy ◽  
Slow Rotation ◽  
Scattering Process ◽  
X Ray ◽  
Spin Reversal ◽  
Stream Model ◽  
Orbital Spin

ABSTRACT Recently, a retrograde neutron star is proposed for the classical wind-fed X-ray pulsar, GX 301-2, to explain the orbital spin-up to spin-down reversal near periastron, based on the stream model invoked to explain the pre-periastron flare of GX 301-2 previously. We study in detail three rare spin-up events detected by Fermi/GBM and find that the spin derivatives are correlated with the Swift/BAT fluxes, following a relation of $\dot{\nu }\propto F^{0.75\pm 0.05}$. All the spin-up events of GX 301-2 started about 10 d after the periastron, which is the time needed for tidally stripped gas to reach the neutron star. The slow rotation of the optical companion implies that the accreted matter is likely to have angular momentum in the direction of the orbital motion, as in a Roche lobe-like overflow. As a result, the spin-up events of GX 301-2 would favour accretion of a prograde disc to a prograde neutron star. We also find that the flare of intrinsic X-ray emission of GX 301-2 happened 0.4 d before periastron, while the flare of low-energy emission (2–10 keV) happened about 1.4 d before periastron. The preceding low-energy flare can be explained by stronger absorption of the intrinsic X-ray emission closer to the periastron. This finding weakened the need of the stream model. The pulse fraction of GX 301-2 near periastron is reduced heavily, which is likely caused by Compton-scattering process. Compton reflection from the optical companion might be responsible for the observed orbital spin reversal of GX 301-2.

scholarly journals Multimessengers from Core-Collapse Supernovae: Multidimensionality as a Key to Bridge Theory and Observation

2012 ◽  
Vol 2012 ◽  
pp. 1-46 ◽  
Author(s):  
Kei Kotake ◽  
Tomoya Takiwaki ◽  
Yudai Suwa ◽  
Wakana Iwakami Nakano ◽  
Shio Kawagoe ◽  
...  
Keyword(s):  
Neutron Star ◽  
Gravitational Waves ◽  
Massive Stars ◽  
Neutrino Flux ◽  
Core Collapse ◽  
Spherically Symmetric ◽  
Hydrodynamic Instabilities ◽  
Important Ingredient ◽  
Hydrodynamic Simulations ◽  
Explosion Mechanism

Core-collapse supernovae are dramatic explosions marking the catastrophic end of massive stars. The only means to get direct information about the supernova engine is from observations of neutrinos emitted by the forming neutron star, and through gravitational waves which are produced when the hydrodynamic flow or the neutrino flux is not perfectly spherically symmetric. The multidimensionality of the supernova engine, which breaks the sphericity of the central core such as convection, rotation, magnetic fields, and hydrodynamic instabilities of the supernova shock, is attracting great attention as the most important ingredient to understand the long-veiled explosion mechanism. Based on our recent work, we summarize properties of gravitational waves, neutrinos, and explosive nucleosynthesis obtained in a series of our multidimensional hydrodynamic simulations and discuss how the mystery of the central engines can be unraveled by deciphering these multimessengers produced under the thick veils of massive stars.

scholarly journals Magnetically assisted explosions of weakly magnetized stars

2017 ◽  
Vol 12 (S331) ◽  
pp. 125-130
Author(s):  
Hidetomo Sawai ◽  
Shoichi Yamada
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
High Resolution ◽  
Stellar Evolution ◽  
Positive Impact ◽  
Core Collapse ◽  
Two Dimensional ◽  
Magnetorotational Instability ◽  
The Magnetic Field ◽  
Large Angular Momentum

AbstractWe carried out high resolution simulations of weakly-magnetized core-collapse supernovae in two-dimensional axisymmetry in order to see the influence of the magnetic field and rotation on the explosion. We found that the magnetic field amplified by magnetorotational instability (MRI) has a great positive impact on the explosion by enhancing the neutrino heating, provided that the progenitor has large angular momentum close to the highest value found in stellar evolution calculations. We also found that even for progenitors neither involving strong magnetic flux nor large angular momentum, the magnetic field is greatly amplified by the convection aand rotation, and this leads to the boost of the explosion again by enhancing the neutrino heating.

scholarly journals Supernovae, Gamma-Ray Bursts and Stellar Rotation

2004 ◽  
Vol 215 ◽  
pp. 601-612 ◽  
Author(s):  
S. E. Woosley ◽  
A. Heger
Keyword(s):  
Angular Momentum ◽  
Neutron Star ◽  
Gamma Ray ◽  
Massive Stars ◽  
Supernova Explosion ◽  
Gamma Ray Bursts ◽  
Iron Core ◽  
Stellar Rotation ◽  
Explosion Mechanism ◽  
Stellar Mergers

One of the most dramatic possible consequences of stellar rotation is its influence on stellar death, particularly of massive stars. If the angular momentum of the iron core when it collapses is such as to produce a neutron star with a period of 5 ms or less, rotation will have important consequences for the supernova explosion mechanism. Still shorter periods, corresponding to a neutron star rotating at break up, are required for the progenitors of gamma-ray bursts (GRBs). Current stellar models, while providing an excess of angular momentum to pulsars, still fall short of what is needed to make GRBs. The possibility of slowing young neutron stars in ordinary supernovae by a combination of neutrino-powered winds and the propeller mechanism is discussed. The fall back of slowly moving ejecta during the first day of the supernova may be critical. GRBs, on the other hand, probably require stellar mergers for their production and perhaps less efficient mass loss and magnetic torques than estimated thus far.

scholarly journals Binary population synthesis models for core-collapse gamma-ray burst progenitors

2019 ◽  
Vol 491 (3) ◽  
pp. 3479-3495 ◽  
Author(s):  
A A Chrimes ◽  
E R Stanway ◽  
J J Eldridge
Keyword(s):  
Angular Momentum ◽  
Stellar Evolution ◽  
Gamma Ray ◽  
Spectral Synthesis ◽  
Host Galaxy ◽  
Core Collapse ◽  
Homogeneous State ◽  
Rotating Stars ◽  
Jet Production ◽  
Post Process

ABSTRACT Long-duration gamma-ray bursts (GRBs) are understood to be the final fate for a subset of massive, stripped envelope, rapidly rotating stars. Beyond this, our knowledge of the progenitor systems is limited. Using the Binary Population and Spectral Synthesis (bpass) stellar evolution models, we investigate the possibility that some massive stars in binaries can maintain the angular momentum required for jet production, while still loosing their outer envelope through winds or binary interactions. We find that a total hydrogen mass of MH < 5 × 10−4 M⊙ and a helium ejecta mass fraction of FHe < 0.20 provide the best thresholds for the supernova type II/Ibc and Ib/Ic divisions, respectively. Tidal interactions in binaries are accounted for by applying a tidal algorithm to post-process the stellar evolution models output by bpass. We show that the observed volumetric GRB rate evolution can be recreated using two distinct pathways and plausible distributions for burst parameters. In the first pathway, stars are spun up by mass accretion into a quasi-homogeneous state. In the second, tides maintain rotation where otherwise the star would spin-down. Both lead to type Ic supernova progenitors, and a metallicity distribution consistent with the GRB host galaxy population. The inferred core angular momentum threshold for jet production is consistent with theoretical requirements for collapsars, given the assumptions made in our model. We can therefore reproduce several aspects of core-collapse supernova/GRB observation and theory simultaneously. We discuss the predicted observable properties of GRB progenitors and their surviving companions.

scholarly journals The pre-supernova evolution of rotating massive stars

2003 ◽  
Vol 212 ◽  
pp. 357-364 ◽  
Author(s):  
Alexander Heger ◽  
Stan E. Woosley ◽  
Norbert Langer
Keyword(s):  
Angular Momentum ◽  
Magnetic Fields ◽  
Main Sequence ◽  
Massive Stars ◽  
Iron Core ◽  
Core Collapse ◽  
Mode Instability ◽  
Angular Momentum Transport ◽  
Explosion Mechanism ◽  
Chemical Mixing

Massive stars are born rotating rigidly with a significant fraction of critical rotation at the surface. Consequently, rotationally-induced circulation and instabilities lead to chemical mixing in regions that would otherwise be stable, as well as a redistribution of angular momentum. Differential rotation also winds up magnetic fields, causing instabilities that can power a dynamo and magnetic stresses that lead to additional angular momentum transport. We follow the evolution of typical massive stars, their structure and angular momentum distribution, from the zero-age main sequence until iron core collapse. Without the action of magnetic fields, the resulting angular momentum is sufficiently large to significantly affect the explosion mechanism and neutron star formation. Sub-millisecond pulsars result that could encounter the r-mode instability. In helium cores massive enough, at least at low metalicity, the angular momentum is also sufficiently great to form a centrifugally supported accretion disk around a central black hole, powering the engine of the ‘collapsar’ model for GRBs. Including current estimates of the effect of magnetic fields still allows the formation of rapidly rotating (~ 5-10 ms) pulsars, but might leave too little angular momentum for collapsars.

scholarly journals Supplying angular momentum to the jittering jets explosion mechanism using inner convection layers

2021 ◽  
Author(s):  
Dmitry Shishkin ◽  
Noam Soker
Keyword(s):  
Angular Momentum ◽  
Three Dimensional ◽  
Mass Range ◽  
Iron Core ◽  
Core Collapse ◽  
Shock Region ◽  
Post Shock ◽  
Explosion Mechanism ◽  
Mixing Length Theory ◽  
Accretion Shock

Abstract We conduct one-dimensional stellar evolution simulations in the mass range 13 − 20M⊙ to late core collapse times and find that an inner vigorous convective zone with large specific angular momentum fluctuations appears at the edge of the iron core during the collapse. The compression of this zone during the collapse increases the luminosity there and the convective velocities, such that the specific angular momentum fluctuations are of the order of $j_{\rm conv} \simeq 5 \times 10^{15} {~\rm cm}^2 {~\rm s}^{-1}$. If we consider that three-dimensional simulations show convective velocities that are three to four times larger than what the mixing length theory gives, and that the spiral standing accretion shock instability in the post-shock region of the stalled shock at a radius of $\simeq 100 {~\rm km}$ amplify perturbations, we conclude that the fluctuations that develop during core collapse are likely to lead to stochastic (intermittent) accretion disks around the newly born neutron star. In reaching this conclusion we also make two basic assumptions with uncertainties that we discuss. Such intermittent disks can launch jets that explode the star in the frame of the jittering jets explosion mechanism.

scholarly journals Millisecond Pulsars

1989 ◽  
Vol 8 ◽  
pp. 161-165
Author(s):  
J.H. Krolik
Keyword(s):  
Neutron Star ◽  
Stellar Evolution ◽  
Close Binary ◽  
Millisecond Pulsar ◽  
Millisecond Pulsars ◽  
Physical Conditions ◽  
Cast Doubt ◽  
Standard Picture ◽  
The Universe ◽  
New System

AbstractMillisecond pulsars are intrinsically interesting because they illustrate some of the most extreme physical conditions to be found anywhere in the Universe, and because their evolution exhibits several stages of great drama. It had been widely believed for several years that spin-up of an old neutron star by accretion from a close stellar companion explained their fast rotation, but the absence of companions in several cases cast doubt on that picture. This spring a millisecond pulsar in a close binary was discovered in which the companion appears to be evaporating, thus reconciling the existence of lone millisecond pulsars with the standard picture. Ongoing observations of this new system, and complementary calculations, promise to answer many of the questions remaining about this dramatic phase in stellar evolution.

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