Abstract We present gas-phase elemental abundance ratios of thirteen local extremely metal-poor galaxies (EMPGs), including our new Keck/LRIS spectroscopy determinations together with 33 James Webb Space Telescope z ∼ 4–10 star-forming in the literature, and compare chemical evolution models. develop models yields core-collapse supernovae (CCSNe), Type Ia SNe, hypernovae (HNe), pair-instability (PISNe), EMPGs high- conjunction dust depletion contributions. find that high Fe/O values can...

We investigate remnant neutron star masses (in particular, the minimum allowed mass) by performing advanced stellar evolution calculations and neutrino-radiation hydrodynamics simulations for core-collapse supernova explosions. find that, based on standard astrophysical scenarios, low-mass carbon-oxygen cores can have sufficiently massive iron that eventually collapse, explode as supernovae, give rise to stars a mass of 1.17 M⊙ – compatible with lowest precisely measured in binary system PSR...

We study explosion characteristics of ultra-stripped supernovae (SNe), which are candidates SNe generating binary neutron stars (NSs). As a first step, we perform stellar evolutionary simulations bare carbon–oxygen cores mass from 1.45 to 2.0 M⊙ until the iron become unstable and start collapsing. then axisymmetric hydrodynamics with spectral neutrino transport using these evolution outcomes as initial conditions. All models exhibit successful explosions driven by heating. The diagnostic...

We investigate light-curve and spectral properties of ultra-stripped core-collapse supernovae. Ultra-stripped supernovae are the explosions heavily stripped massive stars which lost their envelopes via binary interactions with a compact companion star. They eject only ~ 0.1 Msun may be main way to form double neutron-star systems eventually merge emitting strong gravitational waves. follow evolution an supernova progenitor until iron core collapse perform explosive nucleosynthesis...

We perform stellar evolution simulation of first stars and calculate yields from the supernovae. The initial masses are taken 12 to 140 Msun cover whole range core-collapse supernova progenitors, rotation is included, which results in efficient internal mixing. A weak explosion assumed yield calculations, thus only outer distributed matter, not affected by explosive nucleosynthesis, ejected models. show that mass affect yield. All models have abundances [C/O] larger than unity. Stellar...

Energetics of nuclear reaction is fundamentally important to understand the mechanism pair instability supernovae (PISNe). Based on hydrodynamic equations and thermodynamic relations, we derive exact expressions for energy conservation suitable be solved in simulation. We also show that some formulae commonly used literature are obtained as approximations expressions. simulate evolution very massive stars ~100-320 Msun with zero- 1/10 Zsun, calculate further explosions PISNe, applying each...

Many possible scenarios for the formation of multiple stellar populations (MSP) in globular clusters (GCs) have been discussed so far, including involvement asymptotic giant branch stars, fast rotating main sequence very massive stars and mass-transferring binaries based on evolution modelling. But self-consistent, dynamical simulations young GCs are usually not considered. In this work, we perform direct $N$-body modelling such systems with total masses up to $3.2\times10^5$ M$_\odot$,...

(Abridged) We aim at linking the dynamical and radiative properties of remnant SN 1987A to geometrical physical characteristics parent aspherical explosion internal structure its progenitor star. performed 3D hydrodynamic simulations which describe long-term evolution from onset full-fledged age 50 years, accounting for pre-SN The include all processes relevant complex phases interaction SNR with highly inhomogeneous ambient environment around 1987A. From simulations, we synthesize...

We perform three-dimensional hydrodynamic simulations of aspherical core-collapse supernovae focusing on the matter mixing in SN 1987A. The impacts four progenitor (pre-supernova) models and parameterized explosions are investigated. pre-supernova include a blue supergiant (BSG) model based slow merger scenario developed recently for 1987A (Urushibata et al. 2018). others BSG single star evolution two red (RSG) models. Among investigated explosion (simulation) models, with binary an...

The Pr-Y solid-solution of the “1-2-3” crystal structure is expressed as (Pr x Y 1- ) 1+δ Ba 2-δ Cu 3 O y , with δ ranging from 0 ( =0) to 0.06 =1); a small percentage sites are occupied by Pr ions. This for >0.5 nonsuperconducting and does not show metallic conduction. At metal-semiconductor boundary =0.5), average valence ion smaller only ca. 0.1 than that 90 K superconductor YBa 2 7 =0). relation between lattice parameters ionic radii at site completely different empirical obtained so...

We provide progenitor models for electron capture supernovae (ECSNe) with detailed evolutionary calculation. include minor nuclei using a large nuclear reaction network updated rates. For captures, the Coulomb correction on rates is treated and contribution of neutron-rich taken into account in statistical equilibrium (NSE) composition. calculate evolution most massive super asymptotic giant branch stars show that these undergo off-center carbon burnings form ONe cores at center. These get...

While magnetic fields have long been considered to be important for the evolution of non-degenerate stars and compact stars, it has become clear in recent years that actually all are deeply affected. This is particularly true regarding their internal angular momentum distribution, but may also influence mixing processes even fate star. We propose a new framework stellar simulations, which interplay between field, rotation, mass loss, changes density temperature distributions treated...

Binary interactions, especially mass transfer and mergers, can strongly influence the evolution of massive stars change their final properties occurrence supernovae. Here, we investigate how binary interactions affect predictions diffuse flux neutrinos. By performing stellar population syntheses including prescriptions for show that resulting detection rates supernova neutrino background is enhanced by 15%--20% compared to estimates without considerations. A source significant uncertainty...

Observed supermassive black holes in the early universe have several proposed formation channels, part because most of these channels are difficult to probe. One more promising direct collapse a star, has possible probes including explosion helium-core star triggered by general relativistic instability. We develop straightforward method for evaluating radial instability without simplifying assumptions and apply it population III stars taken from post Newtonian stellar evolution code. This is...

as 4.7 V-class cathode materials were prepared with our self-reaction method at 650, 700, and 750°C calcination temperatures respectively, their electrochemical properties crystal structures studied. The sample 700°C was assigned to the space group in X-ray diffraction analysis. On contrary, of calcined 650 or fell into because peaks from missing. showed a one-step profile charge/discharge curve this contrasted other samples showing two-step ones. In spite different structures, these three...

A zero resistance transition temperature of 108 K has been achieved for Pb-doped Bi-Sr-Ca-Cu-O superconductors prepared by conventional powder solid-state reaction. The materials contained both the high Tc phase (Bi2Sr2Ca2Cu3Ox) and low (Bi2Sr2Ca1Cu2Ox). Critical current density at 100 in a magnetic field was 3.5 A/cm2 which larger than that Pb-free sample.

The pair instability supernova (PISN) is a common fate of very massive stars (VMSs). Current theory predicts the initial and CO core mass ranges for PISNe $\sim$140-260 $M_\odot$ $\sim$65-120 respectively that are not much affected by wind loss. corresponding relative event rate between collapse supernovae estimated to be $\sim$1% present-day function. However, no confident PISN candidate has been detected so far, despite more than 1,000 discovered every recent years. We investigate...

Abstract We assess the variance of supernova(SN)-like explosions associated with core collapse rotating massive stars into a black hole-accretion disc system under changes in progenitor structure. Our model central engine evolves hole and through transfer matter angular momentum includes contribution wind. perform two-dimensional, non-relativistic, hydrodynamics simulations using open-source hydrodynamic code Athena++, for which we develop method to calculate self-gravity axially symmetric...

The influence of magnetic fields on stellar evolution remains unresolved. It has been proposed that if there is a large-scale field in the interior, torsional waves could arise, efficiently transporting angular momentum. In fact, observed variations rotation periods some stars can be attributed to these waves' standing waves. We aim demonstrate existence through modeling rotational period variations. conducted an eigenmode analysis based one-dimensional magnetohydrodynamic equations....

Abstract Magnetic hot stars can emit both coherent and incoherent nonthermal radio emission. Understanding the nature of these emissions their connection to stellar rotation magnetic field characteristics remains incomplete. The RAdio Magnetospheres B O (RAMBO) project aims address this gap by systematically detecting characterizing gyrosynchrotron cyclotron maser emission in rapidly rotating stars. Using upgraded Giant Metrewave Radio Telescope, we present first detection from HD 55522 at...

Abstract This paper is a sequel to our 2015 paper, Kato et al., which calculated the luminosities and spectra of electron-type anti-neutrinos ( <?CDATA ${\bar{\nu }}_{e}$?> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mover accent="true"> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mo>¯</mml:mo> </mml:mover> <mml:mi>e</mml:mi> </mml:msub> </mml:math> ) from progenitors core-collapse supernovae. Expecting that capability detect neutrinos ${\nu...

Aiming to distinguish two types of progenitors core-collapse supernovae, i.e., one with a core composed mainly oxygen and neon (abbreviated as ONe core) the other an iron (or Fe core), we calculated luminosities spectra neutrinos emitted from these cores prior gravitational collapse, taking neutrino oscillation into account. We found that total energies are , which is much smaller than for cores. The average energy, on hand, twice large those produced by plasmon decays in more numerous...

When a supernova explosion occurs in neighbors around hundreds pc, current and future neutrino detectors are expected to observe neutrinos from the presupernova star before explosion. We show possibility for obtaining evidence burning processes central region of stars though observations signals by such as KamLAND, JUNO, Hyper-Kamiokande. also investigate alarms using neighbors. If explodes at ~ 200 20 kton size liquid scintillation events. propose detection events Gd-loaded Hyper-Kamiokande...