arXiv subjects

Noam Soker

Publications and source records attributed to Noam Soker.

At least 55 records · Page 3Linked to original sources

arXiv2025

A double-degenerate scenario with a merger to explosion delay time to explain type Ia supernova SN 2020aeuh

I suggest the double-degenerate (DD) scenario with a merger-to-explosion delay (MED) time (the DD-MED scenario) of about 1-2 years to explain the rare properties of the recently analyzed type Ia supernova (SN Ia) SN 2020aeuh. The rare properties are the SN Ia ejecta interacting with a carbon-oxygen (CO)-rich circumstellar material (CSM) at approximately 50 days post-explosion. In this DD-MED scenario, two massive CO white dwarfs (WDs), masses of M1=1.1Mo and M2=1Mo, merge to leave a rapidly rotating lonely WD of about the Chandrasekhar mass. The merger process ejects ~0.7Mo to form a nonspherical CO-rich CSM. At the explosion, there is a lonely WD and a detached hydrogen- and helium-deficient CSM. Studies proposed the other lonely WD scenario, the core-degenerate (CD) scenario, to explain several specific SNe Ia and SN Ia remnants. SN 2020aeuh is the first particular SN Ia that is attributed to the DD-MED scenario. Besides being slightly brighter than typical SNe Ia and the CSM interaction, SN 2020aeuh is a normal SN Ia. Therefore, this study strengthens the claim of earlier studies, which are based on other arguments, like the properties of SN Ia remnants, that the lonely WD scenarios, i.e., the DD-MED and CD scenarios, might account for most, if not all, normal SNe Ia. These earlier studies also argue that all SN Ia scenarios, whether lonely WD or not, might contribute to peculiar SNe Ia.

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arXiv2025

The jet-feedback mechanism in common envelope evolution of planetary nebula progenitors

Using the stellar evolution code MESA, we mimic the negative jet feedback mechanism in common envelope evolution (CEE) of low-mass main sequence stars, M2=0.1-0.2Mo, spiraling inward inside the envelopes of asymptotic giant branch (AGB) or red giant branch (RGB) stars and find that the jets reduced the envelope density, therefore the jets' power, by a factor of ~0.5/(M2/0.1Mo). We mimic the energy that the jets deposit into the envelope by depositing energy into the outer envelope, a process that inflates the envelope, therefore reducing the density in the vicinity of the main sequence star, the accretion rate, and the jets' power. In deriving this expression for the negative jet feedback coefficient, we assume that the actual mass accretion rate is a fraction ~0.2-0.5 of the classical Bondi-Hoyle-Lyttleton mass accretion rate and that the jets carry a fraction ~0.25-0.5 of the accretion energy onto the main sequence star. Our study is another step in establishing the major role of jets in the onset and early phase of CEE, a possible grazing envelope evolution phase, and in transient events, such as luminous red novae, which these processes can power.

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arXiv2025

Natal kick by early-asymmetrical pairs of jets to the neutron star of supernova remnant S147

We analyze the bipolar morphology of the jet-shaped core-collapse supernova (CCSN) remnant (CCSNR) S147 and its neutron star (NS) kick velocity, and suggest that two pairs of unequal, opposite jets contributed to the NS kick velocity. This kick by early asymmetrical pairs (kick-BEAP) of jets mechanism operates within the framework of the jittering jets explosion mechanism (JJEM). We examine the prominent pair of large ears and, based on their flat structure rather than the more common conical structure of ears, conclude that two pairs of jets close in angle inflated the two opposite ears. We connect two opposite X-ray bright zones by an additional axis to create the full point-symmetric morphology of CCSNR S147. We propose that the two unequal jets that formed the X-ray bright zones imparted the first kick-BEAP, while the two pairs of jets that formed the ears imparted the second kick-BEAP. The two kick velocities are of about equal magnitude of ~450 km/s, which implies very energetic jets. Such jets can excite gravitational waves that present detectors can detect from the Galaxy and the Magellanic Clouds. We use the morphology we identify to estimate the CCSNR age at 23,000 yr. Our results strengthen the JJEM.

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arXiv2025

Mass-feeding of jet-launching white dwarfs in grazing and common envelope evolution

I propose a scenario that allows white dwarfs (WDs) to launch relatively powerful jets when they enter a common envelope evolution (CEE) or experience a grazing envelope evolution (GEE) with a red giant branch star (RGB) or an asymptotic giant branch (AGB) star. In this, still a speculative scenario, the accretion for a time is mainly onto an accretion disk with a radius of ~1Ro that increases in mass. The accretion disk launches the powerful two opposite jets by releasing gravitational energy, up to several times super-Eddington, as its mass increases. The jets launched by the disk remove high-entropy gas from its outskirts and the envelope that the WD inflates due to nuclear burning on its surface. The motivations to allow WDs to launch powerful jets are recent findings, from the morphologies of post-CEE planetary nebulae, that jets play a major role in the CEE and the accumulating evidence that jets power luminous red novae by jets, as their morphologies indicate. I strengthen my call to include jets in the simulation and modeling of the CEE, consider the GEE as a phase preceding the CEE in many (but not all) cases, and include jets as a major ingredient in modeling and simulating all energetic luminous red novae.

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arXiv2025

The morphology of supernova remnant G0.9+0.1 implies explosion by jittering-jets

I examine the morphology of the core-collapse supernova (CCSN) remnant (SNR) G0.9+0.1 and reveal a point-symmetrical morphology that implies shaping by three or more pairs of jets, as expected in the jittering jets explosion mechanism (JJEM). The large northwest protrusion, the ear (or lobe), has two bright rims. I compare this ear with its rims to an ear with three rims of a jet-shaped planetary nebula and jets from an active galactic nucleus that shaped several rims on one side. Based on this similarity, I argue that two jets or more shaped the northwest ear of SNR G0.9+0.1 and its two rims. I identified the bright region south of the main shell of SNR G0.9+0.1 as a jet-shaped blowout formed by a jet that broke out from the main SNR shell. I base this on the similarity of the blowout of SNR G0.9+0.1 with that of SNR G309.2-00.6, argued in the past to be shaped by jets. I identify four symmetry axes along different directions that compose the point-symmetric morphology of SNR G0.9+0.1. I show that the morphological features of holes, granular texture, and random filaments exist in CCSNe and planetary nebulae and are unlikely to result from some unique processes in CCSNe. These structures result from similar instabilities in the JJEM and the neutrino-driven explosion mechanism and, unlike a point-symmetric morphology, cannot determine the explosion mechanism. Identifying SNR G0.9+0.1 as a new point-symmetric CCSN strengthens the JJEM as the primary explosion mechanism of CCSNe.

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arXiv2025

Learning from core-collapse supernova remnants on the explosion mechanism

I estimate some typical properties of the jittering jets explosion mechanism (JJEM) to distinguish it from competing supernova explosion models. From the imprints of jittering jets in the outskirts of some CCSN remnants, I estimate the half-opening angles of jittering jets that shape CCSN remnants to be ~1-10 degrees. I also estimate that intermittent accretion disks around the newly born neutron star (NS) can launch jets after they live for only several times their orbital period around the NS. To operate, the JJEM requires intermittent accretion disks that launch jets to amplify the magnetic fields in a dynamo, and the magnetic fields to reconnect and release their energy rapidly. I estimate the width of magnetic field reconnection zones to be ~0.005r~0.1km near the surface of the NS. This width requires a numerical resolution several times smaller than the resolution of present CCSN simulations. I argue, therefore, that existing simulations of the CCSN explosion mechanism are still far from correctly simulating CCSN explosions.

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arXiv2025

The main jet axis of the W49B supernova remnant

We identify an axis connecting two opposite `ears' in the supernova remnant W49B and morphological signatures of three arcs around this axis that we claim are sections of full circum-jet rings. Based on recent identifications of morphological signatures of jets in core-collapse supernovae (CCSNe), including ejecta-rich axes, we reexamine images of W49B and identify a heavy element-rich protrusion (ear) as a jet-inflated structure. We identify the opposite ear and a clump at its tip as the signature of the opposite jets. The line connecting the two clumps at the tips of the two opposite ears forms the main jet axis of W49B. We compare the three arcs around the main jet axis in W49B to the circum-jet rings of the jets in the Cygnus A galaxy and deduce that these arcs are sections of full circum-jet rings in W49B. In W49B, the jets are long gone, as in some planetary nebulae with circum-jet rings. Identifying the main jet axis is incompatible with a type Ia supernova. It leaves two possibilities: that jets exploded W49B as a CCSN, i.e. the jittering jets explosion mechanism where the pair of jets we identify is one of many that exploded the star, or that the explosion was a common envelope jet supernova with a thermonuclear outburst, i.e., both the pair of jets and thermonuclear outburst exploded the core of a red supergiant star as a pre-existing neutron star tidally destroyed it.

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arXiv2025

Mixing neutron star material into the jets in the common envelope jets supernova r-process scenario

I find that the accretion disk around the neutron star (NS) that enters the core of a massive evolved star in the frame of the common-envelope jets supernova (CEJSN) r-process scenario can penetrate the crust of the NS, mix neutron-rich crust material into the disk, and enrich the jets that the disk launches with the neutron-rich material. As the NS accretes at high rates from the core inside which it revolves, it forms an accretion disk with high density. In the CEJSN r-process scenario, the very high density in the accretion disk results in low electron fraction gas, enabling the r-process. Jets carry the r-process elements out. The new claim in this study is that the high-density accretion disk destroys part of the NS crust and entrains this mass. The Kelvin-Helmholtz instability mixes material from the deeper crust. The total neutron-rich mass that the disk mixes and the jets carry can be up to ~0.01Mo. Enriching the accretion disk with neutron-rich material ensures a low electron fraction as required by the r-process nucleosynthesis and the ejection of massive r-process ejecta, 0.01-0.03Mo. I strengthen the CEJSN r-process scenario, but do not claim it is the main r-process site. I only claim that two or more r-process sites contribute to r-process nucleosynthesis.

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arXiv2025

Jet-shaped filamentary ejecta in common envelope evolution

We conduct three-dimensional (3D) hydrodynamical simulations of common envelope evolution (CEE) of a neutron star (NS) that launches jets as it spirals in inside the envelope of a rotating red supergiant (RSG) stellar envelope and find that Rayleigh-Taylor instabilities form filamentary ejecta. We first study the 3D RSG envelope properties before we launch the jets. Adding envelope rotation causes the RSG envelope to expand in the equatorial plane and contract along the poles, leading to non-radial oscillations that decay after two oscillation periods, like the radial oscillation of the non-rotating model. In addition, the envelope becomes convective with large vortices, as in the non-rotating case. Since RSG stars oscillate and have envelope convection, we strengthen the claim that there is no need to relax one-dimensional stellar models of cool giant stars when transporting them to 3D grids. When adding jets, the 3D simulations that include pre-set envelope rotation show that envelope rotation leads to more prominent spiral structures of the ejecta than in the non-rotating case. We map the envelope zones that are Rayleigh-Taylor unstable and conclude that this instability forms the filamentary ejecta, with and without envelope rotation. The jet-inflated high-pressure volumes around the NS accelerate the envelope, a process prone to Rayleigh-Taylor instability.

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arXiv2025

Difficulties of two exploding white dwarfs to account for type Ia supernovae with bimodal nebular emission profiles

We use a simple dynamical scheme to simulate the ejecta of type Ia supernova (SN Ia) scenarios with two exploding white dwarfs (WDs) and find that the velocity distribution of the ejecta has difficulties accounting for bimodal emission line profiles with a large separation between the two emission peaks. The essence of the dynamical code is in including the fact that the ejecta does not leave the system instantaneously. We find that the final separation velocity between the centers of masses of the two WDs' ejecta is ~80% of the pre-explosion WDs' orbital velocity, i.e., we find separation velocities of 4200-5400 km/s for two WDs of masses M1=M2=0.94 Mo. The lower separation velocities we find challenge scenarios with two exploding WDs to explain bimodal emission line profiles with observed velocity separations of up to ~7000 km/s. Only the mass in the ejecta of one WD with an explosion velocity lower than the separation velocity contributes to one peak of the bimodal profile; this is the inner ejecta. We find the inner ejecta to be only <15% of the ejecta mass in energetic explosions. Less energetic explosions yield higher inner mass but lower separation velocities. We encourage searching for alternative explanations of bimodal line profiles.

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arXiv2025

Simulating the shaping of point-symmetric structures in the jittering jets explosion mechanism

We conduct three-dimensional hydrodynamical simulations of core-collapse supernovae by launching several pairs of jets into a collapsing core model and show that the jittering jets explosion mechanism (JJEM) can form a point-symmetric morphology that accounts for observed morphologies of about a dozen core-collapse supernovae (CCSN) remnants. Point-symmetric morphologies are composed of pairs of opposite structures around the center of the CCSN remnant. In the JJEM, the newly born neutron star launches several to a few tens of pairs of jets with stochastically varying directions, and these jets explode the star. In the simulations with the FLASH numerical code, we launch pairs of jets with varying directions, energies, opening angles, and durations into the massive stellar core and follow their evolution for about two seconds. We show that the jets form pairs of opposite filaments, clumps, bubbles, and lobes, namely, prominent point-symmetric morphologies. The interaction of the jets with the core leads to vigorous Rayleigh-Taylor instabilities and excites many vortices, which also shape clumps and filaments. Our results suggest that the JJEM could play a central role in the explosion mechanism of CCSNe; neutrino heating can boost the role of jets.

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arXiv2025

Forming a clumpy circumstellar material in energetic pre-supernova activity

We demonstrate by three-dimensional hydrodynamical simulations of energy deposition into the envelope of a red supergiant (RSG) model the inflation of a Rayleigh-Taylor unstable envelope that forms a compact clumpy circumstellar material (CSM). Our simulations mimic vigorous core activity years to months before a core-collapse supernova (CCSN) explosion that deposits energy to the outer envelope. The fierce core nuclear activity in the pre-CCSN explosion phase might excite waves that propagate to the envelope. The wave energy is dissipated where envelope convection cannot carry the energy. We deposit this energy into a shell in the outer envelope with a power of L(wave)=2.6e6Lo or L(wave)=5.2e5Lo for 0.32 year. The energy-deposition shell expands while its pressure is higher than its surroundings, but its density is lower. Therefore, this expansion is Rayleigh-Taylor unstable and develops instability fingers. Most of the inflated envelope does not reach the escape velocity in the year of simulation but forms a compact and clumpy CSM. The high density of the inflated envelope implies that if a companion is present in that zone, it will accrete mass at a very high rate and power a pre-explosion outburst.

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arXiv2025

On the progenitor of the type Ia supernova remnant 0509-67.5

Based on the iron and hydrogen similar elliptical morphologies of the type Ia supernova (SN Ia) remnant (SNR) 0509-67.5, I suggest that the ambient gas shaped the SN ejecta, that it is a remnant of an old planetary nebula, and that the explosion was spherical. Adding that there is no observed stellar survivor in this SNR, known to be an SN Ia, I conclude that the SN Ia scenarios that best account for the explosion of this SN inside a planetary nebula (SNIP) are the lonely white dwarf scenarios, i.e., the core-degenerate (CD) and the double degenerate (DD) with merger to explosion delay (MED) time, i.e., the DD-MED scenario. Other scenarios encounter challenges, but I cannot completely rule them out. If true, the suggestion of SNR 0509-67.5 being an SNIP implies that the fraction of SNIPs might be higher than the previously estimated 50 percent of all normal SNe Ia. In the frame of the CD and the DD-MED scenarios, I attribute the observed double-shell structure in calcium to Rayleigh-Taylor instability during the explosion process: the caps of the Rayleigh-Taylor instability mushrooms form the outer shell. Instabilities during the explosion process might form clumps of some elements moving much faster than their mean velocity, possibly explaining fast-moving intermediate-mass elements.

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arXiv2025

The Puppis A supernova remnant: an early jet-driven neutron star kick followed by jittering jets

We identify a point-symmetric morphology of three pairs of ears/clumps in the core-collapse supernova remnant (CCSNR) Puppis A, supporting the jittering jets explosion mechanism (JJEM). In the JJEM, the three pairs of jets that shaped the three pairs of ears/clumps in Puppis A are part of a large, about 10 to 30 pairs of jets that exploded Puppis A. Some similarities in morphological features between CCSNR Puppis A and three multipolar planetary nebulae considered to have been shaped by jets solidify the claim for shaping by jets. Puppis A has a prominent dipole structure, where one side is bright with a well-defined boundary, while the other is faint and defused. The neutron star (NS) has a natal kick velocity in the opposite direction to the denser part of the dipole structure. We propose a new mechanism in the frame of the JJEM that imparts a natal kick to the NS, the kick-by-early asymmetrical pair (kick-BEAP) mechanism. At the early phase of the explosion process, the NS launches a pair of jets where one jet is much more energetic than the counter jet. The more energetic jet compresses a dense side to the CCSNR, and, by momentum conservation, the NS recoils in the opposite direction. Our study supports the JJEM as the primary explosion mechanism of core-collapse supernovae and enriches this explosion mechanism by introducing the novel kick-BEAP mechanism.

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arXiv2025

The distribution of misalignment angles in multipolar planetary nebulae

We measure the projected angle on the plane of the sky between adjacent symmetry axes of tens of multipolar planetary nebulae and find that the distribution of these misalignment angles implies a random three-dimensional angle distribution limited to <60 degrees. We identify a symmetry axis as a line connecting two opposite lobes (bubbles) or clumps. We build a cumulative distribution function of the projected angles alpha and find that an entirely random distribution of the three-dimensional angles delta between adjacent symmetry axes, namely, uncorrelated directions, does not fit the observed one. A good fit to the observed distribution is a limited random distribution of the three-dimensional angle between adjacent symmetry axes, i.e., random distribution in the range of 20<delta<60 degrees. We assume that a pair of jets along the angular momentum axis of an accretion disk around the companion shape each symmetry axis. The limited random distribution might result from two sources of angular momentum to the accretion disks with comparable magnitude: one with a fixed direction and one with a stochastic direction variation. We discuss a scenario where the fixed-axis angular momentum source is the binary orbital angular momentum, while the stochastic source of angular momentum is due to the vigorous envelope convection of the mass-losing giant progenitor.

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arXiv2025

Enabling high mass accretion rates onto massive main sequence stars by outer envelope mass removal

Using the one-dimensional numerical code MESA, we simulate mass accretion at very high rates onto massive main sequence stars, M=30, 60, 80 Mo, and find that these stars can accrete up to 10% of their mass without expanding much if we consider a simultaneous mass removal by jets. In this jetted-mass-removal accretion scenario, the accretion is through an accretion disk that launches jets. When the star expands due to rapid mass accretion, it engulfs the inner zones of the accretion disk and the jets it launches. We assume that these jets remove the outer layers of the envelope. We mimic this in the one-dimensional numerical code by alternating mass addition and mass removal parts. We add mass and energy, the accretion energy, to the outer layers of the envelope, leading to rapid stellar expansion. When the star expands by a few tens of percent, we stop mass addition and start mass removal until the star returns to its initial radius. We also show that the density of the accretion disk is larger than the density of the outer layers of the inflated envelope, allowing the disk to launch jets inside the outer inflated envelope layers. Our results show that main sequence stars can accrete mass at high rates while maintaining the deep potential well, as some models of eruptive systems require, e.g., some luminous red novae, the grazing envelope evolution, and the 1837-1856 Great Eruption of Eta Carinae.

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arXiv2025

The vela supernova remnant: The unique morphological features of jittering jets

We identify an S-shaped main-jet axis in the Vela core-collapse supernova (CCSN) remnant (CCSNR) that we attribute to a pair of precessing jets, one of the tens of pairs of jets that exploded the progenitor of Vela according to the jittering jets explosion mechanism (JJEM). A main-jet axis is a symmetry axis across the CCSNR and through the center. We identify the S-shaped main-jet axis by the high abundance of ejecta elements, oxygen, neon, and magnesium. We bring the number of identified pairs of clumps and ears in Vela to seven, two pairs shaped by the pair of precessing jets that formed the main-jet axis. The pairs and the main-jet axis form the point-symmetric wind-rose structure of Vela. The other five pairs of clumps/ears do not have signatures near the center, only on two opposite sides of the CCSNR. We discuss different possible jet-less shaping mechanisms to form such a point-symmetric morphology and dismiss these processes because they cannot explain the point-symmetric morphology of Vela, the S-shaped high ejecta abundance pattern, and the enormous energy to shape the S-shaped structure. Our findings strongly support the JJEM and further severely challenge the neutrino-driven explosion mechanism.

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arXiv2025

Jets are the most robust observable ingredient of common envelope evolution

I examine images of 50 planetary nebulae (PNe) with observable post-common envelope evolution (CEE) binary central stars and find that jets are about 40 percent more common than dense equatorial outflows. Because, in some cases, energetic jets can compress an equatorial outflow and because fast jets might disperse early in the PN evolution and avoid detection, the CEE process is likelier to launch jets than to eject a dense equatorial outflow by a larger factor than 1.4. In most cases, the companion, mainly a main sequence star, launches the jets as it accretes mass from the envelope of the giant star. By CEE jets, I also refer to jets launched shortly before the onset of the CEE, likely a grazing envelope evolution phase, and shortly after the CEE. The jets and the accretion of mass by the companion before, during, and after the CEE affect envelope mass removal and the final orbital separation. Most numerical simulations of the CEE ignore jets, and those that include jets omit other processes. Despite the considerable progress in the last decade with tens of hydrodynamical simulations of the CEE, we are still far from correctly simulating the CEE. Including jets in simulations of the CEE requires heavy computer resources, but it must be the next step.

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