arXiv subjects

Noam Soker

Publications and source records attributed to Noam Soker.

At least 163 records · Page 9Linked to original sources

arXiv2020

Eccentric grazing envelope evolution towards type IIb supernova progenitors

We simulate the evolution of eccentric binary systems in the frame of the grazing envelope evolution (GEE) channel for the formation of Type IIb supernovae (SNe IIb), and find that extra mass removal by jets increases the parameter space for the formation of SNe IIb in this channel. To explore the role of eccentricity and the extra mass removal by jets we use the stellar evolutionary code MESA binary. The initial primary and secondary masses are M1i=15Mo and M2i=2.5Mo. We examine initial semi-major axes of 600-1000Ro, and eccentricities of e=0-0.9. Both Roche lobe overflow (RLOF) and mass removal by jets, followed by a wind, leave a hydrogen mass in the exploding star of M(H,f)=0.05Mo, compatible with a SN IIb progenitor. When the initial orbit is not circular the final orbit might have a very high eccentricity. In many cases, with and without the extra mass removal by jets, the system can enter a common envelope evolution (CEE) phase, and then gets out from it. For some ranges of eccentricities the jets are more efficient in preventing the CEE. Despite the large uncertainties, extra mass removal by jets substantially increases the likelihood of the system to get out from a CEE. This strengthens earlier conclusions for circular orbits. In some cases RLOF alone, without mass removal by jets, can form SN IIb progenitors. We estimate that the extra mass removal by jets in the GEE channel increases the number of progenitors relative to that by RLOF alone by about a factor of two.

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arXiv2020

Jet-driven active galactic nucleus feedback in galaxy formation before black hole formation

We propose a scenario where during galaxy formation an active galactic nucleus (AGN) feedback mechanism starts before the formation of a supermassive black hole (SMBH). The supermassive star (SMS) progenitor of the SMBH accretes mass as it grows and launches jets. We simulate the evolution of SMSs and show that the escape velocity from their surface is approximately several 10^3 km/s, with large uncertainties. We could not converge with the parameters of the evolutionary numerical code MESA to resolve the uncertainties for SMS evolution. Under the assumption that the jets carry about ten percent of the mass of the SMS, we show that the energy in the jets is a substantial fraction of the binding energy of the gas in the galaxy/bulge. Therefore, the jets that the SMS progenitor of the SMBH launches carry sufficient energy to establish a feedback cycle with the gas in the inner zone of the galaxy/bulge, and hence, set a relation between the total stellar mass and the mass of the SMS. As the SMS collapses to form the SMBH at the center, there is already a relation (correlation) between the newly born SMBH mass and the stellar mass of the galaxy/bulge. During the formation of the SMBH it rapidly accretes mass from the collapsing SMS and launches very energetic jets that might unbind most of the gas in the galaxy/bulge.

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arXiv2020

On the role of reduced wind mass-loss rate in enabling exoplanets to shape planetary nebulae

We use the stellar evolution code MESA-binary and follow the evolution of three exoplanets and two brown dwarfs (BDs) to determine their potential role in the future evolution of their parent star on the red giant branch (RGB) and on the asymptotic giant branch (AGB). We limit this study to exoplanets and BDs with orbits that have semi-major axis of 1AU 0.25, and having a parent star of mass M>1Mo. We find that the star HIP 75458 will engulf its planet HIP 75458 b during its RGB phase. The planet will remove the envelope and terminate the RGB evolution, leaving a bare helium core of mass 0.4Mo that will evolve to form a helium white dwarf. Only in one system out of five, the planet beta Pic c will enter the envelope of its parent star during the AGB phase. For that to occur, we have to reduce the wind mass-loss rate by a factor of about four from its commonly used value. This strengthens an early conclusion, which was based on exoplanets with circular orbits, that states that to have a non-negligible fraction of AGB stars that engulf planets we should consider lower wind mass-loss rates of isolated AGB stars (before they are spun-up by a companion). Such an engulfed planet might lead to the shaping of the AGB mass-loss geometry to form an elliptical planetary nebula.

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arXiv2020

Jet-shaped geometrically modified light curves of core collapse supernovae

We build three simple bipolar ejecta models for core collapse supernovae (CCSNe), as expected when the explosion is driven by strong jets, and show that for an observer located in the equatorial plane of the ejecta, the light curve has a rapid luminosity decline, and even an abrupt drop. In calculating the geometrically modified photosphere we assume that the ejecta has an axisymmetrical structure composed of an equatorial ejecta and faster polar ejecta, and has a uniform effective temperature. At early times the photosphere in the polar ejecta grows faster than the equatorial one, leading to higher luminosity relative to a spherical explosion. The origin of the extra radiated energy is the jets. At later times the optical depth decreases faster in the polar ejecta, and the polar photosphere becomes hidden behind the equatorial ejecta for an observer in the equatorial plane, leading to a rapid luminosity decline. For a model where the jets inflate two low-density polar bubbles, the luminosity decline might be abrupt. This model enables us to fit the abrupt decline in the light curve of SN 2018don.

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arXiv2020

Supernovae Ia in 2019 (review): a rising demand for spherical explosions

I review new studies of type Ia supernovae (SNe Ia) from 2019, and use these to improve the comparison between the five binary SN Ia scenarios. New low polarisation measurements solidify the claim that most SN Ia explosions are globally spherically symmetric (clumps are possible). Explosions by dynamical processes, like explosions that take place during a merger process of two white dwarfs (WDs) in the double degenerate (DD) scenario, or during an accretion process in the double detonation (DDet) scenario and in the single degenerate (SD) scenario, lead to non-spherical explosions, in contradiction with observations of normal SNe Ia. I argue that these (DD, DDet, SD) scenarios account mainly for peculiar SNe Ia. The explosion of a Chandrasekhar mass (Mch) WD (deflagration to detonation process) has a global spherical structure that is compatible with observations. To reach spherical explosions, SN Ia scenarios should allow for a time delay between the formation of an Mch-WD and its explosion. As such, I split the DD scenario to a channel without merger to explosion delay (MED) time (that forms mainly peculiar SNe Ia), and a channel with a MED, the DD-MED channel (scenario). I speculate that the main contributors to normal SNe Ia are the core degenerate (CD) scenario, the DD-MED scenario, both have Mch spherical explosions, and the DD scenario that has sub-Mch non-spherical explosions.

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arXiv2020

Kinematics of filaments in cooling flow clusters and heating by mixing

We compare a recent study of the kinematics of optical filaments in three cooling flow clusters of galaxies with previous numerical simulations of jet-inflated hot bubbles, and conclude that the velocity structure functions of the filaments better fit direct excitation by the jets than by turbulent cascade from the largest turbulent eddies. The observed velocity structure functions of the optical filaments in the three clusters are steeper than that expected from a classical cascade in turbulent dissipation. Our three-dimensional (3D) hydrodynamical simulations show that as the jets inflate bubbles in the intracluster medium (ICM), they form vortexes in a large range of scales. These vortexes might drive the ICM turbulence with eddies of over more than an order of magnitude in size. A direct excitation of turbulence by the vortexes that the jets form and the slow turbulent dissipation imply that heating the ICM by mixing with hot bubbles is more efficient than heating by turbulent dissipation.

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arXiv2020

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

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 \textsc{mesa}. For the lowest stellar masses, we study, $M_{\rm ZAMS} \simeq 8.5-11 M_\odot$, 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 $M_{\rm NS} \approx 1.25M_\odot-1.6M_\odot$, even for these low energy CCSNe.

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arXiv2020

Enhanced mass-loss rate evolution of stars with $\gtrsim 18 M_\odot$ and missing optically-observed type II core-collapse supernovae

We evolve stellar models with zero-age main sequence (ZAMS) mass of $M_{\rm ZAMS} \gtrsim 18 M_\odot$ under the assumption that they experience an enhanced mass-loss rate when crossing the instability strip at high luminosities and conclude that most of them end as type Ibc supernovae (SNe Ibc) or dust-obscured SNe II. We explore what level of enhanced mass-loss rate during the instability strip would be necessary to explain the `red supergiant (RSG) problem'. This problem refers to the dearth of observed core-collapse supernovae progenitors with $M_{\rm ZAMS} \gtrsim 18 M_\odot$. Namely, we examine what enhanced mass loss rate could make it possible for all these stars actually to explode as CCSNe. We find that the mass-loss rate should increase by a factor of at least about ten. We reach this conclusion by analyzing the hydrogen mass in the stellar envelope and the optical depth of the dusty wind at the explosion, and crudely estimate that under our assumptions only about a fifth of these stars explode as unobscured SNe II and SNe IIb. About 10-15 per cent end as obscured SNe II that are infrared-bright but visibly very faint, and the rest, about 65-70 per cent, end as SNe Ibc. However, the statistical uncertainties are still too significant to decide whether many stars with $M_{\rm ZAMS} \gtrsim 18M_\odot$ do not explode as expected in the neutrino driven explosion mechanism, or whether all of them explode as CCSNe, as expected by the jittering jets explosion mechanism.

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arXiv2020

Efficiently jet-powered radiation in intermediate-luminosity optical transients (ILOTS)

I show that a flow structure where wide jets hit a slower expanding shell might be very efficient in channelling the kinetic energy of the jets to radiation, therefore accounting for, at a least a fraction of, intermediate luminosity optical transients (ILOTs) where the total radiation energy is much larger than what recombination energy of the outflow can supply. This type of flow might occur in the frame of the high-accretion-powered ILOT (HAPI) model, where there is a high mass accretion rate as a result of stellar merger or mass transfer in a binary system. I derive the condition on the jets half-opening angle for the jets not to penetrate through the slow shell, as well as the ratio of the photon diffusion time to expansion time. This ratio cannot be too large if a large fraction of the thermal energy is channelled to radiation. I apply the jet-powered radiation model to the Great Eruption of Eta Carinae, to V838~Mon, and to V4332~Sgr, and find a plausible set of parameters for these ILOTs. I expect the jet-powered radiation model to be more efficient in converting kinetic energy to radiation than ILOT models that are based on equatorial mass concentration. In many cases, thought, I expect both jets and equatorial mass concentration to occur in the same system.

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arXiv2020

Shaping planetary nebulae with jets and the grazing envelope evolution

I argue that the high percentage of PNe that are shaped by jets show that main sequence stars in binary systems can accrete mass at a high rate from an accretion disk and launch jets. Not only this allows jets to shape PNe, but this also points to the importance of jets in other types of binary systems and in other processes. These processes include the grazing envelope evolution (GEE), the common envelope evolution (CEE), and the efficient conversion of kinetic energy to radiation in outflows. As well, the jets point to the possibility that many systems launch jets as they enter the CEE, possibly through a GEE phase. The other binary systems where jets might play significant roles include intermediate-luminosity optical transients (ILOTs), supernova impostors (including pre-explosion outbursts), post-CEE binary systems, post-GEE binary systems, and progenitors of neutron star binary systems and black hole binary systems. One of the immediate consequences is that the outflow of these systems is highly-non-spherical, including bipolar lobes, jets, and rings.

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arXiv2020

A companion star launching jets in the wind acceleration zone of a giant star

By conducting three-dimensional (3D) hydrodynamical simulations we find that jets that a main sequence companion launches as it orbits inside the wind acceleration zone of an asymptotic giant branch (AGB) star can efficiently remove mass from that zone. We assume that during the intensive wind phase a large fraction of the gas in the acceleration zone does not reach the escape velocity. Therefore, in the numerical simulations we blow the wind with a velocity just below the escape velocity. We assume that a main sequence companion accretes mass from the slow wind via an accretion disk, and launches two opposite jets perpendicular to the equatorial plane. This novel flow interaction shows that by launching jets a companion outside a giant star, but close enough to be in the acceleration zone of a slow intensive wind, can enhance the mass loss rate from the giant by ejecting some gas that would otherwise fall back onto the giant star. The jets are bent inside the wind acceleration zone and eject mass in a belt on the two sides of the equatorial plane. The jet-wind interaction contains instabilities that mix shocked jets' gas with the wind, leading to energy transfer from the jets to the wind. As well, our new simulations add to the rich variety of jet-induced outflow morphologies from evolved stars.

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arXiv2020

Emission peaks in the light curve of core collapse supernovae by late jets

We build a toy model where the central object, i.e., a newly born neutron star or a black hole, launches jets at late times and show that these jets might account for peaks in the light curve of some peculiar (i.e., having unusual light curves) core collapse supernovae (CCSNe) when the jets interact with the CCSN ejecta. We assume that the central object accretes fallback material and launches two short-lived opposite jets weeks to months after the explosion. We model each jet-ejecta interaction as a spherically symmetric `mini explosion' that takes place inside the ejecta. We assume that each `mini explosion' adds emission that is symmetric in time around the late peak, and with a rise in emission power that has the same slope as that of the main CCSN light curve. In total we use 12 parameters in the toy model. In our toy model late jets form stronger emission peaks than early jets. Late jets with a kinetic energy of only about one percent of the kinetic energy of the CCSN itself might form strong emission peaks. We apply our toy model to the brightest peak of the enigmatic CCSN iPTF14hls that has several extra peaks in its light curve. We can fit this emission peak with our toy model when we take the kinetic energy of the jets to be about one to two percent of the CCSN energy, and the shocked ejecta mass to be about three percent of the ejecta mass.

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arXiv2019

Type IIb supernovae by the grazing envelope evolution

We simulate the evolution of binary systems with a massive primary star of 15Mo where we introduce an enhanced mass loss due to jets that the secondary star might launch, and find that in many cases the enhanced mass loss brings the binary system to experience the grazing envelope evolution (GEE) and form a progenitor of Type IIb supernova (SN IIb). The jets, the Roche lobe overflow (RLOF), and a final stellar wind remove most of the hydrogen-rich envelope, leaving a blue-compact SN IIb progenitor. In many cases without this jet-driven mass loss the system enters a common envelope evolution (CEE) and does not form a SN IIb progenitor. We use the stellar evolutionary code MESA binary and mimic the jet-driven mass loss with a simple prescription and some free parameters. Our results show that the jet-driven mass loss, that some systems have during the GEE, increases the parameter space for stellar binary systems to form SN IIb progenitors. We estimate that the binary evolution channel with GEE contributes about a quarter of all SNe IIb, about equal to the contribution of each of the other three channels, binary evolution without a GEE, fatal CEE (where the secondary star merges with the core of the giant primary star), and the single star channel.

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arXiv2019

Evaporating Planets in SNe Ia

I suggest that in rare cases type Ia supernovae (SNe Ia) evaporate Jupiter-like planets that reside within a=50Ro from the SN, accounting for the presence of ~0.001Mo of hydrogen in the ejecta. It is not easy to form such planets. The common envelope evolution (CEE) might end with the formation of a circumbinary disk with a typical size of R(disk)~10-50Ro. However, the bright central star might prevent the formation of planets. Alternatively, the planets might be first-generation planets that survived the entire evolution. Interestingly, all five SN Ia binary scenarios (core degenerate; double degenerate; double detonation; single degenerate; WD-WD collision) might account for the presence of planets.

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arXiv2019

Inclined jets inside a common envelope of a triple stellar system

We conduct a three-dimensional hydrodynamical simulation to study the interaction of two opposite inclined jets inside the envelope of a giant star, and find that the jets induce many vortexes inside the envelope and that they efficiently remove mass from the envelope and form a very clumpy outflow. We assume that this very rare type of interaction occurs when a tight binary system enters the envelope of a giant star, and that the orbital plane of the tight binary system and that of the triple stellar system are inclined to each other. We further assume that one of the stars of the tight binary system accretes mass and launches two opposite jets and that the jets' axis is inclined to the angular momentum axis of the triple stellar system. The many vortexes that the jets induce along the orbit of the tight binary system inside the giant envelope might play an important role in the common envelope evolution (CEE) by distributing energy in the envelope. The density fluctuations that accompany the vortexes lead to an outflow with many clumps that might facilitate the formation of dust. This outflow lacks any clear symmetry, and it might account for very rare types of `messy' planetary nebulae and `messy' nebulae around massive stars. On a broader scope, our study adds to the notion that jets can play important roles in the CEE, and that they can form a rich variety of shapes of nebulae around evolved stars.

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arXiv2019

Common envelope to explosion delay time of type Ia supernovae

I study the rate of type Ia supernovae (SNe Ia) within about a million years after the assumed common envelope evolution (CEE) that forms the progenitors of these SNe Ia, and find that the population of SNe Ia with short CEE to explosion delay (CEED) time is ~fewx0.1 of all SNe Ia. I also claim for an expression for the rate of these SNe Ia that occur at short times after the CEE, t(CEED)<10^6 year, that is different from that of the delay time distribution (DTD) billions of years after star formation. This tentatively hints that the physical processes that determine the short CEED time distribution (CEEDTD) are different (at least to some extend) from those that determine the DTD at billions of years. To reach these conclusions I examine SNe Ia that interact with a circumstellar matter (CSM) within months after explosion, so called SNe Ia-CSM, and the rate of SNe Ia that on a time scale of tens to hundreds of years interact with a CSM that might have been a planetary nebula, so called SNe Ia inside a planetary nebula (SNIPs). I assume that the CSM in these populations results from a CEE, and hence this study is relevant mainly to the core degenerate (CD) scenario, to the double degenerate (DD) scenario, to the double detonation (DDet) scenario with white dwarf companions, and to the CEE-wind channel of the single degenerate (SD) scenario.

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arXiv2019

Towards a paradigm change in the main heavy r-process nucleosynthesis sites

We study the basic properties of three possible r-process scenarios (sites) and compare them to recent observations and theoretical simulations. We find that the common envelope jets supernova (CEJSN) r-process scenario can account for the different observations of r-process nucleosynthesis, including the presence of r-process-rich low-metalicity stars in ultra-faint dwarf (UFD) galaxies. The neutron star (NS)-NS merger scenario and the collapsar scenario encounter some difficulties. Despite that, we conclude that it is very likely that more than one r-process scenario exists, with a significant contribution by the CEJSN r-process scenario. We give a prescription to include this scenario in population synthesis studies of the r-process.

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arXiv2019

Type IIb supernova progenitors by fatal common envelope evolution

From stellar evolution simulations (using MESA) we conclude that the fatal common envelope evolution (CEE) channel for the formation of Type IIb core collapse supernova (SN IIb) progenitors can indeed account for some SNe IIb. In the fatal CEE channel for SNe IIb a low mass main sequence secondary star inspirals inside the giant envelope of the massive primary star and removes most of the giant envelope before it merges with the giant core. The key ingredient of the scenario studied here is that the tidally destroyed secondary star forms a new giant envelope. The mass-loss process in a wind during the evolution from the merger process until core collapse, i.e., until the explosion, leaves little hydrogen mass at explosion as inferred from observations of SNe IIb. In the case of a massive primary star with a zero age main sequence mass of M(ZAMS)=16Mo that during its giant phase swallows a main sequence star of mass M2=0.5Mo, we find at explosion a hydrogen mass of M(H)=0.02-0.09Mo, depending on the rotation we assume. We find similar values for M(ZAMS)=12Mo.

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