scholarly journals Pre-supernova activity as a possible explanation of the peculiar properties of Type IIP supernova 2009kf

2020 ◽  
Vol 500 (2) ◽  
pp. 1889-1894
Author(s):  
Ryoma Ouchi ◽  
Keiichi Maeda
Keyword(s):  
Observational Data ◽  
Explosion Energy ◽  
Core Collapse ◽  
Plateau Phase ◽  
The Core ◽  
V Band ◽  
Constant Rate

ABSTRACT SN 2009kf is an exceptionally bright Type IIP supernova (SN IIP) discovered by the Pan-STARRS 1 survey. The V-band magnitude in the plateau phase is MV = −18.4 mag, which is much brighter than that for typical SNe IIP. We propose that its unusual properties can be naturally explained if we assume that there was a super-Eddington energy injection into the envelope in the last few years of the evolution before the SN explosion. Using a progenitor model with such a pre-SN energy injection, we can fit the observational data of SN 2009kf with a reasonable explosion energy of Eexp = 2.8 × 1051 erg and 56Ni mass of 0.25 M⊙. Specifically, we injected the energy into the envelope at a constant rate of 3.0 × 1039 erg s−1 in the last 3.0 yr of evolution before the core collapse. We propose that some unusually bright SNe IIP might result from pre-SN energy injection into the envelope.

scholarly journals The origin of the two populations of blue stragglers in M30

2019 ◽  
Vol 621 ◽  
pp. L10 ◽  
Author(s):  
S. Portegies Zwart
Keyword(s):  
Stellar Evolution ◽  
Main Sequence ◽  
The Other ◽  
Core Collapse ◽  
Blue Stragglers ◽  
The Core ◽  
Constant Rate ◽  
Blue Straggler ◽  
Binary Evolution ◽  
Two Populations

We analyze the position of the two populations of blue stragglers in the globular cluster M30 in the Hertzsprung–Russell diagram. Both populations of blue stragglers are brighter than the cluster’s turn-off, but one population, the blue blue-stragglers, aligns along the zero-age main sequence whereas the other, red population is elevated in brightness (or color) by ∼0.75 mag. Based on stellar evolution and merger simulations we argue that the red population, which composes about 40% of the blue stragglers in M 30, has formed at a constant rate of ∼2.8 blue stragglers per gigayear over the last ∼10 Gyr. The blue population on the other hand formed in a burst that started ∼3.2 Gyr ago at a peak rate of 30 blue stragglers per gigayear with an e-folding time scale of 0.93 Gyr. We speculate that the burst resulted from the core collapse of the cluster at an age of about 9.8 Gyr, whereas the constantly formed population is the result of mass transfer and mergers through binary evolution. In this scenario, about half the binaries in the cluster effectively result in a blue straggler.

scholarly journals Hypernovae: SNe 1997ef, 1998bw, and 1997cy

2000 ◽  
Vol 195 ◽  
pp. 347-357 ◽  
Author(s):  
T. Nakamura ◽  
K. Maeda ◽  
K. Iwamoto ◽  
T. Suzuki ◽  
K. Nomoto ◽  
...  
Keyword(s):  
Light Curve ◽  
Massive Stars ◽  
Explosion Energy ◽  
Core Collapse ◽  
Spectral Features ◽  
The Core ◽  
Normal Core

We discuss the properties of the very energetic Type Ic supernovae (SNe Ic) 1998bw and 1997ef, and of Type IIn supernova (SN IIn) 1997cy. SNe Ic 1998bw and 1997ef are characterized by their large luminosity and very broad spectral features. Their observed properties can be explained if they are very energetic SN explosions (EK ≳ 1 × 1052 erg), originating probably from the core collapse of the bare C+O cores of massive stars (~ 30–40M⊙). At late times, both the light curve and the spectra suggest that the explosion may have been asymmetric; this may help us understand the claimed connection with GRBs. Type IIn SN 1997cy is even more luminous than SN 998bw, and the light curve declines more slowly than the 56Co decay. We model such a light curve with circumstellar interaction, which requires the explosion energy of ~ 5 × 1052 erg. Because these kinetic energies of explosion are much larger than in normal core-collapse SNe, we call objects like these SNe “hypernovae”.

scholarly journals Dynamical Evolution of Globular Clusters After Core Collapse

1985 ◽  
Vol 113 ◽  
pp. 139-160 ◽  
Author(s):  
Douglas C. Heggie
Keyword(s):  
Surface Density ◽  
Globular Clusters ◽  
Stellar System ◽  
Dynamical Evolution ◽  
Theoretical Models ◽  
Numerical Calculations ◽  
Core Collapse ◽  
Density Profiles ◽  
The Core ◽  
Fokker Planck

This review describes work on the evolution of a stellar system during the phase which starts at the end of core collapse. It begins with an account of the models of Hénon, Goodman, and Inagaki and Lynden-Bell, as well as evaporative models, and modifications to these models which are needed in the core. Next, these models are related to more detailed numerical calculations of gaseous models, Fokker-Planck models, N-body calculations, etc., and some problems for further work in these directions are outlined. The review concludes with a discussion of the relation between theoretical models and observations of the surface density profiles and statistics of actual globular clusters.

scholarly journals Pinning down the superfluid and measuring masses using pulsar glitches

2015 ◽  
Vol 1 (9) ◽  
pp. e1500578 ◽  
Author(s):  
Wynn C. G. Ho ◽  
Cristóbal M. Espinoza ◽  
Danai Antonopoulou ◽  
Nils Andersson
Keyword(s):  
Observational Data ◽  
New Technique ◽  
Timing Behavior ◽  
Fundamental Physics ◽  
X Ray ◽  
The Core ◽  
Timing Precision ◽  
A New Technique

Pulsars are known for their superb timing precision, although glitches can interrupt the regular timing behavior when the stars are young. These glitches are thought to be caused by interactions between normal and superfluid matter in the crust of the star. However, glitching pulsars such as Vela have been shown to require a superfluid reservoir that greatly exceeds that available in the crust. We examine a model in which glitches tap the superfluid in the core. We test a variety of theoretical superfluid models against the most recent glitch data and find that only one model can successfully explain up to 45 years of observational data. We develop a new technique for combining radio and x-ray data to measure pulsar masses, thereby demonstrating how current and future telescopes can probe fundamental physics such as superfluidity near nuclear saturation.

scholarly journals Luminous supernovae associated with ultra-long gamma-ray bursts from hydrogen-free progenitors extended by pulsational pair-instability

2020 ◽  
Vol 641 ◽  
pp. L10
Author(s):  
Takashi J. Moriya ◽  
Pablo Marchant ◽  
Sergei I. Blinnikov
Keyword(s):  
Light Curve ◽  
Energy Input ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Core Collapse ◽  
Decay Energy ◽  
Slow Cooling ◽  
Gamma Ray Burst ◽  
The Core ◽  
Optical Light Curve

We show that the luminous supernovae associated with ultra-long gamma-ray bursts can be related to the slow cooling from the explosions of hydrogen-free progenitors that are extended by pulsational pair-instability. We have recently shown that some rapidly-rotating hydrogen-free gamma-ray burst progenitors that experience pulsational pair-instability can keep an extended structure caused by pulsational pair-instability until the core collapse. These types of progenitors have large radii exceeding 10 R⊙ and they sometimes reach beyond 1000 R⊙ at the time of the core collapse. They are, therefore, promising progenitors of ultra-long gamma-ray bursts. Here, we perform light-curve modeling of the explosions of one extended hydrogen-free progenitor with a radius of 1962 R⊙. The progenitor mass is 50 M⊙ and 5 M⊙ exists in the extended envelope. We use the one-dimensional radiation hydrodynamics code STELLA in which the explosions are initiated artificially by setting given explosion energy and 56Ni mass. Thanks to the large progenitor radius, the ejecta experience slow cooling after the shock breakout and they become rapidly evolving (≲10 days), luminous (≳1043 erg s−1) supernovae in the optical even without energy input from the 56Ni nuclear decay when the explosion energy is more than 1052 erg. The 56Ni decay energy input can affect the light curves after the optical light-curve peak and make the light-curve decay slowly when the 56Ni mass is around 1 M⊙. They also have a fast photospheric velocity above 10 000 km s−1 and a hot photospheric temperature above 10 000 K at around the peak luminosity. We find that the rapid rise and luminous peak found in the optical light curve of SN 2011kl, which is associated with the ultra-long gamma-ray burst GRB 111209A, can be explained as the cooling phase of the extended progenitor. The subsequent slow light-curve decline can be related to the 56Ni decay energy input. The ultra-long gamma-ray burst progenitors we proposed recently can explain both the ultra-long gamma-ray burst duration and the accompanying supernova properties. When the gamma-ray burst jet is off-axis or choked, the luminous supernovae could be observed as fast blue optical transients without accompanying gamma-ray bursts.

scholarly journals Effects of Small-Scale Fluctuations of Neutrino Flux in Supernova Explosions

2005 ◽  
Vol 192 ◽  
pp. 309-314
Author(s):  
Hideki Madokoro ◽  
Tetsuya Shimizu ◽  
Yuko Motizuki
Keyword(s):  
Neutrino Flux ◽  
Explosion Energy ◽  
Small Scale ◽  
Core Collapse ◽  
Effective Mechanism ◽  
Core Collapse Supernova ◽  
Neutrino Radiation ◽  
Spherical Explosion ◽  
Supernova Explosions ◽  
Neutrino Luminosity

SummaryWe examine effects of small-scale fluctuations with angle in the neutrino radiation in core-collapse supernova explosions. As the mode number of fluctuations increases, the results approach those of spherical explosion. We conclude that global anisotropy of the neutrino radiation is the most effective mechanism of increasing the explosion energy when the total neutrino luminosity is given.

scholarly journals Effects of Hardness of Primordial Binaries on Evolution of Star Clusters

2007 ◽  
Vol 3 (S246) ◽  
pp. 251-255
Author(s):  
A. Tanikawa ◽  
T. Fukushige
Keyword(s):  
Star Clusters ◽  
Equal Mass ◽  
Binding Energies ◽  
The Other ◽  
Special Treatment ◽  
Integration Scheme ◽  
Core Collapse ◽  
The Core ◽  
Double Mass

AbstractWe performed N-body simulations of star clusters with primordial binaries using a new code, GORILLA. It is based on Makino and Aarseth (1992)'s integration scheme on GRAPE, and includes a special treatment for relatively isolated binaries. Using the new code, we investigated effects of hardness of primordial binaries on whole evolution of the clusters. We simulated seven N=16384 equal-mass clusters containing 10% (in mass) primordial binaries whose binding energies are 1, 3, 10, 30, 100, 300, and 1000kT, respectively. Additionally, we also simulated a cluster without primordial binaries and that in which all binaries are replaced by stars with double mass, as references of soft and hard limits, respectively. We found that, in both soft (≤ 3kT) and hard (≥ 1000kT) limits, clusters experiences deep core collapse and shows gravothermal oscillations. On the other hands, in the intermediate hardness (10-300kT), the core collapses halt halfway due an energy releases of the primordial binaries.

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