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The Neutron Star to Black Hole Mass Gap in the Frame of the Jittering Jets Explosion Mechanism(JJEM)

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Research in Astronomy and Astrophysics 2023年第9期23卷 213-218页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

I build a toy model in the frame of the jittering jets explosion mechanism(JJEM)of core collapse supernovae that incorporates both the stochastically varying angular momentum component of the material that the newly born neutron star(NS)accretes and the constant angular momentum component,and show that the JJEM can account for the≃2.5–5M⊙mass gap between NSs and black holes(BHs).The random component of the angular momentum results from pre-collapse core convection fluctuations that are amplified by post-collapse *** fixed angular momentum component results from pre-collapse core *** slowly rotating pre-collapse cores the stochastic angular momentum fluctuations form intermittent accretion disks(or belts)around the NS with varying angular momentum axes in all *** intermittent accretion disk/belt launches jets in all directions that expel the core material in all directions early on,hence leaving an NS *** rotating pre-collapse cores form an accretion disk with angular momentum axis that is about the same as the pre-collapse core *** NS launches jets along this axis and hence the jets avoid the equatorial plane *** core material continues to feed the central object from the equatorial plane increasing the NS mass to form a *** narrow transition from slow to rapid pre-collapse core rotation,i.e.,from an efficient to inefficient jet feedback mechanism,accounts for the sparsely populated mass gap.

关键词： stars massive-stars neutron-stars black holes-(stars )supernovae general-stars jets

Supernovae Ia in 2017:a long time delay from merger/accretion to explosion

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Science China(Physics,Mechanics & Astronomy) 2018年第4期61卷 7-16页

作者： noam soker Department of Physics Technion-lsrael Institute of TechnologyHaifa 32000Israel Guangdong Technion Israel Institute of Technology shantou 515063China

I use recent observational and theoretical studies of type Ia supernovae(SNe Ia) to further constrain the viable SN Ia scenarios and to argue that there must be a substantial time delay between the end of the merger of the white dwarf(WD) with a companion or the end of mass accretion on to the WD and its terminal explosion. This merger/accretion to explosion delay(MED) is required to allow the binary system to lead to a more or less spherical explosion and to prevent a pre-explosion ionizing radiation. Considering these recent results and the required MED, I conclude that the core degenerate scenario is somewhat more favorable over the other scenarios, followed by the double degenerate scenario. Although the single degenerate scenario is viable as well, it is less likely to account for common(normal) SN Ia. As all scenarios require substantial MED, the MED has turned from a disadvantage of the core degenerate scenario to a challenge that theory should overcome. I hope that the requirement for a MED will stimulate the discussion of the different SN Ia scenarios and the comparison of the scenarios to each other.

关键词： supernovae supernova remnants cataclysmic binaries binary and multiple stars

A Pre-explosion Effervescent Zone for the Circumstellar Material in SN 2023ixf

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Research in Astronomy and Astrophysics 2023年第8期23卷 5-9页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

I present the effervescent zone model to account for the compact dense circumstellar material(CSM)around the progenitor of the core collapse supernova(CCSN)SN *** effervescent zone is composed of bound dense clumps that are lifted by stellar pulsation and envelope convection to distances of≈tens×au,and then fall *** dense clumps provide most of the compact CSM mass and exist alongside the regular(escaping)wind.I crudely estimate that for a compact CSM within R_(CSM)≈30 au that contains M_(CSM)≈0.01 M_(⊙),the density of each clump is k_(b)≳3000 times the density of the regular wind at the same radius and that the total volume filling factor of the clumps is several *** clumps might cover only a small fraction of the CCSN photosphere in the first days post-explosion,accounting for the lack of strong narrow absorption *** long-lived effervescent zone is compatible with no evidence for outbursts in the years prior to the SN 2023ixf explosion and the large-amplitude pulsations of its progenitor,and it is an alternative to the CSM scenario of several-years-long high mass loss rate wind.

关键词： stars massive-stars mass-loss (stars:)supernovae general-(stars:)supernovae individual(SN 2023ixf)

The class of supernova progenitors that result from fatal common envelope evolution

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Science China(Physics,Mechanics & Astronomy) 2019年第11期62卷 35-46页

作者： noam soker Department of Physics Technion – Israel Institute of Technology Guangdong Technion Israel Institute of Technology

I construct the class of supernovae and supernova progenitors that result from fatal common envelope evolution(CEE). The fatal CEE progenitors are stellar binary systems where a companion spirals-in inside the envelope of a giant star and merges with the core. The companion can be a neutron star(NS;or a black hole) that destroys the core and by that forms a common envelope jets supernova(CEJSN), a white dwarf(WD) that merges with the core to form a massive WD that later might explode as a Type Ia supernova(the core degenerate scenario), or a main sequence companion. In the latter case the outcome might be a core collapse supernova(CCSN) of a blue giant, a CCSN of type IIb or of type Ib. In another member of this class two giant stars merge and the two cores spiral-in toward each other to form a massive core that later explodes as a CCSN with a massive circumstellar matter(CSM). I discuss the members of this class, their characteristics, and their common properties. I find that fatal CEE events account for ≈6%-10% of all CCSNe, and raise the possibility that a large fraction of peculiar and rare supernovae result from the fatal CEE. The study of these supernova progenitors as a class will bring insights on other types of supernova progenitors, as well as on the outcome of the CEE.

关键词： common envelope evolution(CEE) supernovae binary and multiple stars neutron stars white dwarfs

Supernova 1987A's Keyhole:A Long-lived Jet-pair in the Final Explosion Phase of Core-collapse Supernovae

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Research in Astronomy and Astrophysics 2024年第7期24卷 89-94页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

I further study the manner by which a pair of opposite jets shape the“keyhole”morphological structure of the core-collapse supernova(CCSN)SN 1997A,now the CCSN remnant(CCSNR)*** doing so,I strengthen the claim that the jittering-jet explosion mechanism accounts for most,likely all,***“keyhole”structure comprises a northern low-intensity zone closed with a bright rim on its front and an elongated low-intensity nozzle in the *** rim-nozzle asymmetry is observed in some cooling flow clusters and planetary nebulae that are observed to be shaped by jets.I build a toy model that uses the planar jittering jets pattern,where consecutive pairs of jets tend to jitter in a common plane,implying that the accreted gas onto the newly born neutron star at the late explosion phase flows perpendicular to that *** allows for a long-lived jet-launching *** long-lasting jet-launching episode launches more mass into the jets that can inflate larger pairs of ears or bubbles,forming the main jets'axis of the CCSNR that is not necessarily related to a possible pre-collapse core rotation.I discuss the relation of the main jets'axis to the neutron star's natal kick velocity.

关键词： stars massive-(stars)supernovae general-(stars)supernovae individual(SN 1987A)-ISM supernova remnants-stars jets

Classifying Core Collapse Supernova Remnants by Their Morphology as Shaped by the Last Exploding Jets

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Research in Astronomy and Astrophysics 2023年第11期23卷 150-160页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

Under the assumption that jets explode all core collapse supernovae(CCSNe),I classify 14 CCSN remnants(CCSNRs)into five groups according to their morphology as shaped by jets,and attribute the classes to the specific angular momentum of the pre-collapse ***-symmetry(one CCSNR):According to the jittering jets explosion mechanism(JJEM)when the pre-collapse core rotates very slowly,the newly born neutron star(NS)launches tens of jet-pairs in all *** last several jet-pairs might leave an imprint of several pairs of“ears,”i.e.,a point-symmetric *** pair of ears(eight CCSNRs):More rapidly rotating cores might force the last pair of jets to be long-lived and shape one pair of jet-inflated ears that dominates the morphology.S-shaped(one CCSNR):The accretion disk might precess,leading to an S-shaped ***-shaped(three CCSNRs):Even more rapidly rotating pre-collapse cores might result in a final energetic pair of jets that clear the region along the axis of the pre-collapse core rotation and form a barrel-shaped ***(one CCSNR):A very rapidly rotating pre-collapse core forces all jets to be along the same axis such that the jets are inefficient in expelling mass from the equatorial plane and the long-lasting accretion process turns the NS into a black *** two new results of this study are the classification of CCSNRs into five classes based on jet-shaped morphological features,and the attribution of the morphological classes mainly to the pre-collapse core rotation in the frame of the JJEM.

关键词： stars:massive stars:neutron stars:black holes (stars:)supernovae:general ISM:supernova remnants stars:jets

Predicting Gravitational Waves from Jittering-jets-driven Core Collapse Supernovae

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Research in Astronomy and Astrophysics 2023年第12期23卷 1-6页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

I estimate the frequencies of gravitational waves from jittering jets that explode core collapse supernovae(CCSNe)to crudely be 5–30 Hz,and with strains that might allow detection of Galactic *** jittering jets explosion mechanism(JJEM)asserts that most CCSNe are exploded by jittering jets that the newly born neutron star(NS)launches within a few *** to the JJEM,instabilities in the accreted gas lead to the formation of intermittent accretion disks that launch the jittering *** studies that did not include jets calculated the gravitational frequencies that instabilities around the NS emit to have a peak in the crude frequency range of 100–*** on a recent study,I take the source of the gravitational waves of jittering jets to be the turbulent bubbles(cocoons)that the jets inflate as they interact with the outer layers of the core of the star at thousands of kilometers from the *** lower frequencies and larger strains than those of gravitational waves from instabilities in CCSNe allow future,and maybe present,detectors to identify the gravitational wave signals of jittering *** of gravitational waves from local CCSNe might distinguish between the neutrino-driven explosion mechanism and the JJEM.

关键词： gravitational waves-stars neutron-stars black holes-(stars )supernovae general-stars jets

Boosting Jittering Jets by Neutrino Heating in Core Collapse Supernovae

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Research in Astronomy and Astrophysics 2022年第9期22卷 77-87页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

I estimate the energy that neutrino heating adds to the outflow that jets induce in the collapsing core material in core collapse supernovae(CCSNe), and find that this energy crudely doubles the energy that the jets deposit into the outer core. I consider the jittering jets explosion mechanism where there are several stochastic jet-launching episodes, each lasting for about 0.01–0.1 s. The collapsing core material passes through the stalled shock at about100 km and then slowly flows onto the proto-neutron star(NS). I assume that the proto-NS launches jittering jets,and that the jets break out from the stalled shock. I examine the boosting process by which the high-pressure gas inside the stalled shock, the gain region material, expands alongside the jets and does work on the material that the jets shock, the cocoon. This work is crudely equal to the energy that the original jets carry. I argue that the coupling between instabilities, stochastic rotation, magnetic fields, and jittering jets leads to most CCSN explosions. In other cases, the pre-collapse core is rapidly rotating and therefore ordered rotation replaces stochastic rotation and fixed jets replace jittering jets.

关键词： stars:supernovae:general stars:jets ISM:supernova remnants

A Common Envelope Jets Supernova(CEJSN) Impostor Scenario for Fast Blue Optical Transients

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Research in Astronomy and Astrophysics 2022年第5期22卷 87-97页

作者： noam soker Department of Physics TechnionHaifa3200003Israel

I propose a new scenario,the polar common envelope jets supernova(CEJSN)impostor scenario,to account for AT2018 cow-like fast blue optical transients(FBOTs).The polar CEJSN impostor scenario evolves through four main phases.(1)A red supergiant(RSG)star expands to tidally interact with a neutron star(NS)companion(or a black hole).The interaction increases the RSG mass loss rate to form a circumstellar matter(CSM)halo to r■0.1 pc.(2)Shortly before the onset of a common envelope evolution(CEE)and about a year before explosion the NS accretes mass from the RSG envelope and launches jets that inflate two opposite lobes in the CSM within≈100 au.(3)The NS-RSG system enters a CEE phase during which the system ejects most of the envelope mass in a dense equatorial outflow.(4)At the termination of the CEE the leftover envelope forms a circumbinary disk around the NS-core *** NS accretes mass from the circumbinary disk and launches energetic jets that,when colliding with the fronts of the CSM lobes,power an FBOT *** low mass of the jets-lobes interaction zones and their large distance,of about 100 au,from the center account for the fast *** the future the core collapses to form a second *** the far future the two NSs might merge.I suggest that FBOTs and similar fast transients are CEJSN impostors which compose a large fraction of the progenitors of NS-NS merger binaries.

关键词： neutron stars-supernovae-stellar jets-common envelope binary stars-transient sources