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 Wave heating from proto-neutron star convection and the core-collapse supernova explosion mechanism

2019 ◽  
Vol 491 (4) ◽  
pp. 5376-5391 ◽  
Author(s):  
Sarah E Gossan ◽  
Jim Fuller ◽  
Luke F Roberts
Keyword(s):  
Acoustic Waves ◽  
Supernova Explosion ◽  
Core Collapse ◽  
Core Collapse Supernova ◽  
The Core ◽  
Shock Region ◽  
Wave Heating ◽  
Post Shock ◽  
Explosion Mechanism ◽  
Proto Neutron Star

ABSTRACT Our understanding of the core-collapse supernova explosion mechanism is incomplete. While the favoured scenario is delayed revival of the stalled shock by neutrino heating, it is difficult to reliably compute explosion outcomes and energies, which depend sensitively on the complex radiation hydrodynamics of the post-shock region. The dynamics of the (non-)explosion depend sensitively on how energy is transported from inside and near the proto-neutron star (PNS) to material just behind the supernova shock. Although most of the PNS energy is lost in the form of neutrinos, hydrodynamic and hydromagnetic waves can also carry energy from the PNS to the shock. We show that gravity waves excited by core PNS convection can couple with outgoing acoustic waves that present an appreciable source of energy and pressure in the post-shock region. Using one-dimensional simulations, we estimate the gravity wave energy flux excited by PNS convection and the fraction of this energy transmitted upwards to the post-shock region as acoustic waves. We find wave energy fluxes near $10^{51}\, \mathrm{erg}\, \mathrm{s}^{-1}\,$ are likely to persist for $\sim \! 1\, \mathrm{s}$ post-bounce. The wave pressure on the shock may exceed $10{{\ \rm per\ cent}}$ of the thermal pressure, potentially contributing to shock revival and, subsequently, a successful and energetic explosion. We also discuss how future simulations can better capture the effects of waves, and more accurately quantify wave heating rates.

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 Three-dimensional models of core-collapse supernovae from low-mass progenitors with implications for Crab

2020 ◽  
Vol 496 (2) ◽  
pp. 2039-2084 ◽  
Author(s):  
G Stockinger ◽  
H-T Janka ◽  
D Kresse ◽  
T Melson ◽  
T Ertl ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Iron Core ◽  
Core Collapse ◽  
Crab Pulsar ◽  
Core Collapse Supernova ◽  
Spin Period ◽  
The Core ◽  
Low Mass ◽  
Catch Up ◽  
Three Dimensional Models

ABSTRACT We present 3D full-sphere supernova simulations of non-rotating low-mass (∼9 M⊙) progenitors, covering the entire evolution from core collapse through bounce and shock revival, through shock breakout from the stellar surface, until fallback is completed several days later. We obtain low-energy explosions (∼0.5–1.0 × 1050 erg) of iron-core progenitors at the low-mass end of the core-collapse supernova (LMCCSN) domain and compare to a super-AGB (sAGB) progenitor with an oxygen–neon–magnesium core that collapses and explodes as electron-capture supernova (ECSN). The onset of the explosion in the LMCCSN models is modelled self-consistently using the vertex-prometheus code, whereas the ECSN explosion is modelled using parametric neutrino transport in the prometheus-HOTB code, choosing different explosion energies in the range of previous self-consistent models. The sAGB and LMCCSN progenitors that share structural similarities have almost spherical explosions with little metal mixing into the hydrogen envelope. A LMCCSN with less second dredge-up results in a highly asymmetric explosion. It shows efficient mixing and dramatic shock deceleration in the extended hydrogen envelope. Both properties allow fast nickel plumes to catch up with the shock, leading to extreme shock deformation and aspherical shock breakout. Fallback masses of $\mathord {\lesssim }\, 5\, \mathord {\times }\, 10^{-3}$ M⊙ have no significant effects on the neutron star (NS) masses and kicks. The anisotropic fallback carries considerable angular momentum, however, and determines the spin of the newly born NS. The LMCCSN model with less second dredge-up results in a hydrodynamic and neutrino-induced NS kick of >40 km s−1 and a NS spin period of ∼30 ms, both not largely different from those of the Crab pulsar at birth.

Recent Status of Multi-Dimensional Core-Collapse Supernova Models

2015 ◽  
Vol 11 (A29A) ◽  
pp. 340-344
Author(s):  
Kei Kotake ◽  
Ko Nakamura ◽  
Tomoya Takiwaki
Keyword(s):  
Energy Transport ◽  
Unique Feature ◽  
Three Dimensional ◽  
Radiation Hydrodynamics ◽  
Core Collapse ◽  
Core Collapse Supernova ◽  
Self Consistent ◽  
New Type ◽  
Explosion Mechanism ◽  
Proto Neutron Star

AbstractWe report a recent status of multi-dimensional neutrino-radiation hydrodynamics simulations for clarifying the explosion mechanism of core-collapse supernovae (CCSNe). In this contribution, we present two results, one from two-dimensional (2D) simulations using multiple progenitor models and another from three-dimensional (3D) rotational core-collapse simulation using a single progenitor. From the first ever systematic 2D simulations, it is shown that the compactness parameter ξ that characterizes the structure of the progenitors is a key to diagnose the explodability of neutrino-driven explosions. In the 3D rotating model, we find a new type of rotation-assisted explosion, which makes the explosion energy bigger than that in the non-rotating model. The unique feature has not been captured in previous 2D self-consistent rotational models because the growth of non-axisymmetric instabilities is the key to foster the explosion by enhancing the energy transport from the proto-neutron star to the gain region.

scholarly journals The impact of progenitor asymmetries on the neutrino-driven convection in core-collapse supernovae

2020 ◽  
Vol 494 (4) ◽  
pp. 5360-5373 ◽  
Author(s):  
Rémi Kazeroni ◽  
Ernazar Abdikamalov
Keyword(s):  
Buoyant Density ◽  
Three Dimensional ◽  
Core Collapse ◽  
Wide Range ◽  
Order Of Magnitude ◽  
Post Shock ◽  
Nuclear Burning ◽  
Density Perturbations ◽  
Perturbation Parameters ◽  
The Impact

ABSTRACT The explosion of massive stars in core-collapse supernovae may be aided by the convective instabilities that develop in their innermost nuclear burning shells. The resulting fluctuations support the explosion by generating additional turbulence behind the supernova shock. It was suggested that the buoyant density perturbations arising from the interaction of the pre-collapse asymmetries with the shock may be the primary contributor to the enhancement of the neutrino-driven turbulent convection in the post-shock region. Employing three-dimensional numerical simulations of a toy model, we investigate the impact of such density perturbations on the post-shock turbulence. We consider a wide range of perturbation parameters. The spatial scale and the amplitude of the perturbations are found to be of comparable importance. The turbulence is particularly enhanced when the perturbation frequency is close to that of the convective turnovers in the gain region. Our analysis confirms that the buoyant density perturbations is indeed the main source of the additional turbulence in the gain region, validating the previous order-of-magnitude estimates.

scholarly journals Spectropolarimetry of stripped-envelope supernovae: observations and modelling

2017 ◽  
Vol 375 (2105) ◽  
pp. 20160273 ◽  
Author(s):  
Masaomi Tanaka
Keyword(s):  
Large Scale ◽  
Massive Stars ◽  
Three Dimensional ◽  
Core Collapse ◽  
Ion Distribution ◽  
Typical Size ◽  
Cassiopeia A ◽  
Accretion Shock

Spectropolarimetry is one of the most powerful methods to study the multi-dimensional geometry of supernovae (SNe). We present a brief summary of the spectropolarimetric observations of stripped-envelope core-collapse SNe. Observations indicate that stripped-envelope SNe generally have a non-axisymmetric ion distribution in the ejecta. Three-dimensional clumpy geometry nicely explains the observed properties. A typical size of the clumps deduced from observations is relatively large: 25% of the photosphere. Such a large-scale clumpy structure is similar to that observed in Cassiopeia A, and suggests that large-scale convection or standing accretion shock instability takes place at the onset of the explosion. This article is part of the themed issue ‘Bridging the gap: from massive stars to supernovae’.

scholarly journals Gravitational-wave signals from 3D supernova simulations with different neutrino-transport methods

2021 ◽  
Vol 503 (3) ◽  
pp. 3552-3567
Author(s):  
H Andresen ◽  
R Glas ◽  
H-Th Janka
Keyword(s):  
Gravitational Wave ◽  
Main Sequence ◽  
Core Collapse ◽  
Numerical Resolution ◽  
Hydrodynamic Behaviour ◽  
Post Shock ◽  
High Resolution Models ◽  
Accretion Shock ◽  
The Impact ◽  
Bubble Convection

ABSTRACT We compare gravitational-wave (GW) signals from eight 3D simulations of core-collapse supernovae, using two different progenitors with zero-age main-sequence masses of 9 and 20 solar masses (M⊙). The collapse of each progenitor was simulated four times, at two different grid resolutions and with two different neutrino transport methods, using the aenus-alcar code. The main goal of this study is to assess the validity of recent concerns that the so-called ‘Ray-by-Ray+’ (RbR+) approximation is problematic in core-collapse simulations and can adversely affect theoretical GW predictions. Therefore, signals from simulations using RbR+ are compared to signals from corresponding simulations using a fully multidimensional (FMD) transport scheme. The 9 M⊙ progenitor successfully explodes, whereas the 20 M⊙ model does not. Both the standing accretion shock instability and hot-bubble convection develop in the post-shock layer of the non-exploding models. In the exploding models, neutrino-driven convection in the post-shock flow is established around 100 ms after core bounce and lasts until the onset of shock revival. We can, therefore, judge the impact of the numerical resolution and neutrino transport under all conditions typically seen in non-rotating core-collapse simulations. We find excellent qualitative agreement in all GW features. We find minor quantitative differences between simulations, but find no systematic differences between simulations using different transport schemes. Resolution-dependent differences in the hydrodynamic behaviour of low-resolution and high-resolution models have a greater impact on the GW signals than consequences of the different transport methods. Furthermore, increasing the resolution decreases the discrepancies between models with different neutrino transport.

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 Core-collapse supernova neutrino emission and detection informed by state-of-the-art three-dimensional numerical models

2020 ◽  
Vol 500 (1) ◽  
pp. 696-717 ◽  
Author(s):  
Hiroki Nagakura ◽  
Adam Burrows ◽  
David Vartanyan ◽  
David Radice
Keyword(s):  
Numerical Models ◽  
Three Dimensional ◽  
Neutrino Energy ◽  
Reconstruction Technique ◽  
Core Collapse ◽  
Cumulative Number ◽  
Core Collapse Supernova ◽  
Interesting Correlation ◽  
Time Variations ◽  
Accretion Shock

ABSTRACT Based on our recent three-dimensional core-collapse supernova (CCSN) simulations including both exploding and non-exploding models, we study the detailed neutrino signals in representative terrestrial neutrino observatories, namely Super-Kamiokande (Hyper-Kamiokande), DUNE, JUNO, and IceCube. We find that the physical origin of difference in the neutrino signals between 1D and 3D is mainly proto-neutron-star convection. We study the temporal and angular variations of the neutrino signals and discuss the detectability of the time variations driven by the spiral standing accretion shock instability (spiral SASI) when it emerges for non-exploding models. In addition, we determine that there can be a large angular asymmetry in the event rate (${\gtrsim} 50 {{\ \rm per\ cent}}$), but the time-integrated signal has a relatively modest asymmetry (${\lesssim} 20 {{\ \rm per\ cent}}$). Both features are associated with the lepton-number emission self-sustained asymmetry and the spiral SASI. Moreover, our analysis suggests that there is an interesting correlation between the total neutrino energy (TONE) and the cumulative number of neutrino events in each detector, a correlation that can facilitate data analyses of real observations. We demonstrate the retrieval of neutrino energy spectra for all flavours of neutrino by applying a novel spectrum reconstruction technique to the data from multiple detectors. We find that this new method is capable of estimating the TONE within the error of ∼20 per cent if the distance to the CCSN is ≲6 kpc.

scholarly journals Three‐Dimensional Simulations of Standing Accretion Shock Instability in Core‐Collapse Supernovae

2008 ◽  
Vol 678 (2) ◽  
pp. 1207-1222 ◽  
Author(s):  
Wakana Iwakami ◽  
Kei Kotake ◽  
Naofumi Ohnishi ◽  
Shoichi Yamada ◽  
Keisuke Sawada
Keyword(s):  
Three Dimensional ◽  
Core Collapse ◽  
Accretion Shock ◽  
Three Dimensional Simulations
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