supernova explosion
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2022 ◽  
Vol 163 (2) ◽  
pp. 60
Author(s):  
Ye Wang ◽  
Biwei Jiang ◽  
Jun Li ◽  
He Zhao ◽  
Yi Ren

Abstract The dust temperature and mass of the supernova remnants (SNRs) in M31 are estimated by fitting the infrared spectral energy distribution calculated from the images in the Spitzer/IRAC4 and MIPS24, Herschel/PACS70, 100, and 160, and Herschel/SPIRE 250 and 350 μm bands. Twenty SNRs with relatively reliable photometry exhibit an average dust temperature of 20.1 − 1.5 + 1.8 K, which is higher than the surrounding and indicating the heating effect of supernova explosion. The dust mass of these SNRs ranges from about 100 to 800 M ⊙, much bigger than the SNRs in the Milky Way. On the other hand, this yields the dust surface density of 0.10 − 0.04 + 0.07 M ⊙ pc−2, about half of the surrounding area, which implies that about half dust in the SNRs is destroyed by the supernova explosion. The dust temperature, the radius, and thus the dust mass all demonstrate that the studied SNRs are old and very likely in the snowplow or even fade-away phase because of the limitation by the far distance and observation resolution of M31, and the results can serve as a reference to the final effect of supernova explosion on the surrounding dust.


2021 ◽  
Vol 922 (2) ◽  
pp. 266
Author(s):  
Zhan Bai ◽  
Wei-jie Fu ◽  
Yu-xin Liu

Abstract We investigate the nonradial oscillations of newly born neutron stars (NSs) and strange quark stars (SQSs). This is done with the relativistic nuclear field theory with hyperon degrees of freedom employed to describe the equation of state (EoS) for the stellar matter in NSs, and with both the MIT bag model and the Nambu–Jona-Lasinio model adopted to construct the configurations of the SQSs. We find that the gravitational-mode (g-mode) eigenfrequencies of newly born SQSs are significantly lower than those of NSs, which is independent of models implemented to describe the EoS for the strange quark matter. Meanwhile, the eigenfrequencies of the other modes of nonradial oscillations, e.g., fundamental (f)- and pressure (p)-modes, are much larger than those of the g-mode, and are related to the stiffness of the EoSs. In light of the first direct observation of gravitational waves (GWs), it is promising to employ GWs to identify the QCD phase transition in high-density strong-interaction matter.


2021 ◽  
Vol 923 (1) ◽  
pp. L8
Author(s):  
Ji-an Jiang ◽  
Keiichi Maeda ◽  
Miho Kawabata ◽  
Mamoru Doi ◽  
Toshikazu Shigeyama ◽  
...  

Abstract In this Letter we report a discovery of a prominent flash of a peculiar overluminous Type Ia supernova, SN 2020hvf, in about 5 hr of the supernova explosion by the first wide-field mosaic CMOS sensor imager, the Tomo-e Gozen Camera. The fast evolution of the early flash was captured by intensive intranight observations via the Tomo-e Gozen high-cadence survey. Numerical simulations show that such a prominent and fast early emission is most likely generated from an interaction between 0.01 M ⊙ circumstellar material (CSM) extending to a distance of ∼1013 cm and supernova ejecta soon after the explosion, indicating a confined dense CSM formation at the final evolution stage of the progenitor of SN 2020hvf. Based on the CSM–ejecta interaction-induced early flash, the overluminous light curve, and the high ejecta velocity of SN 2020hvf, we suggest that the SN 2020hvf may originate from a thermonuclear explosion of a super-Chandrasekhar-mass white dwarf (“super-M Ch WD”). Systematical investigations on explosion mechanisms and hydrodynamic simulations of the super-M Ch WD explosion are required to further test the suggested scenario and understand the progenitor of this peculiar supernova.


2021 ◽  
Vol 923 (1) ◽  
pp. 20
Author(s):  
Xiaoying Pang ◽  
Zeqiu Yu ◽  
Shih-Yun Tang ◽  
Jongsuk Hong ◽  
Zhen Yuan ◽  
...  

Abstract We identify hierarchical structures in the Vela OB2 complex and the cluster pair Collinder 135 and UBC 7 with Gaia EDR3 using the neural network machine-learning algorithm StarGO. Five second-level substructures are disentangled in Vela OB2, which are referred to as Huluwa 1 (Gamma Velorum), Huluwa 2, Huluwa 3, Huluwa 4, and Huluwa 5. For the first time, Collinder 135 and UBC 7 are simultaneously identified as constituent clusters of the pair with minimal manual intervention. We propose an alternative scenario in which Huluwa 1–5 have originated from sequential star formation. The older clusters Huluwa 1–3, with an age of 10–22 Myr, generated stellar feedback to cause turbulence that fostered the formation of the younger-generation Huluwa 4–5 (7–20 Myr). A supernova explosion located inside the Vela IRAS shell quenched star formation in Huluwa 4–5 and rapidly expelled the remaining gas from the clusters. This resulted in global mass stratification across the shell, which is confirmed by the regression discontinuity method. The stellar mass in the lower rim of the shell is 0.32 ± 0.14 M ⊙ higher than in the upper rim. Local, cluster-scale mass segregation is observed in the lowest-mass cluster Huluwa 5. Huluwa 1–5 (in Vela OB2) are experiencing significant expansion, while the cluster pair suffers from moderate expansion. The velocity dispersions suggest that all five groups (including Huluwa 1A and Huluwa 1B) in Vela OB2 and the cluster pair are supervirial and are undergoing disruption, and also that Huluwa 1A and Huluwa 1B may be a coeval young cluster pair. N-body simulations predict that Huluwa 1–5 in Vela OB2 and the cluster pair will continue to expand in the future 100 Myr and eventually dissolve.


Author(s):  
Ubiratãn José Furtado ◽  
Sidney dos Santos Avancini ◽  
José Ricardo Marinelli

Abstract Pairing effects in non-uniform nuclear matter, surrounded by electrons, are studied in the protoneutron star early stage and in other conditions. The so-called nuclear pasta phases at sub saturation densities are solved in a Wigner-Seitz cell, within the Thomas-Fermi approximation. The solution of this problem is important for the understanding of the physics of a newly born neutron star after a supernova explosion. It is shown that the pasta phase is more stable than uniform nuclear matter on some conditions and the pairing force relevance is studied in the determination of these stable phases.


2021 ◽  
Vol 922 (1) ◽  
pp. 3
Author(s):  
Shao-Peng Tang ◽  
Yin-Jie Li ◽  
Yuan-Zhu Wang ◽  
Yi-Zhong Fan ◽  
Da-Ming Wei

Abstract In a binary system, the gravitational potential of the primary black hole may play an important role in enhancing the fallback accretion onto the lighter compact object newly formed in the second supernova explosion. As a result, the final masses of the binary compact objects would be correlated, as suggested recently by Safarzadeh & Wysocki. In this work, we analyze the mass distribution of four gravitational-wave events, which are characterized by both a small mass ratio and a low mass (≤5M ⊙) of the light component, and find tentative evidence for a mass correlation among the objects. To evaluate the feasibility of testing such a hypothesis with upcoming observations, we carry out simulations with a mock population and perform Bayesian hierarchical inference for the mass distribution. We find that with dozens of low mass ratio events, whether there exists correlation in the component mass distributions or not can be robustly tested and the correlation, if it exists, can be well determined.


Author(s):  
Andrei P Igoshev ◽  
Martyna Chruslinska ◽  
Andris Dorozsmai ◽  
Silvia Toonen

Abstract Supernova explosion and the associated neutron star natal kicks are important events on a pathway of a binary to become a gravitational wave source, an X-ray binary or a millisecond radio pulsar. Weak natal kicks often lead to binary survival, while strong kicks frequently disrupt the binary. In this article, we aim to further constrain neutron star natal kicks in binaries. We explore binary population synthesis models by varying prescription for natal kick, remnant mass and mass accretion efficiency. We introduce a robust statistical technique to analyse combined observations of different nature. Using this technique, we further test different models using parallax and proper motion measurements for young isolated radio pulsars and similar measurements for Galactic Be X-ray binaries. Our best model for natal kicks is consistent with both measurements and contains a fraction of w = 0.2 ± 0.1 weak natal kicks with $\sigma _1 = 45^{+25}_{-15}$ km s−1, the remaining natal kicks are drawn from the high-velocity component, same as in previous works: σ2 = 336 km s−1. We found that currently used models for natal kicks of neutron stars produced by electron capture supernova (combination of maxwellian σ = 265 km s−1 and σ = 30 km s−1 for electron capture) are inconsistent or marginally consistent with parallaxes and proper motions measured for isolated radio pulsars. We suggest a new model for natal kicks of ecSN, which satisfy both observations of isolated radio pulsars and Be X-ray binaries.


2021 ◽  
Vol 57 (9) ◽  
Author(s):  
Tobias Fischer

AbstractThe nature of core-collapse supernova (SN) explosions is yet incompletely understood. The present article revisits the scenario in which the release of latent heat due to a first-order phase transition, from normal nuclear matter to the quark–gluon plasma, liberates the necessary energy to explain the observed SN explosions. Here, the role of the metallicity of the stellar progenitor is investigated, comparing a solar metallicity and a low-metallicity case, both having a zero-age main sequence (ZAMS) mass of 75 M$$_\odot $$ ⊙ . It is found that low-metallicity models belong exclusively to the failed SN branch, featuring the formation of black holes without explosions. It excludes this class of massive star explosions as possible site for the nucleosynthesis of heavy elements at extremely low metallicity, usually associated with the early universe.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Sofya Alexeeva ◽  
Gang Zhao ◽  
Dong-Yang Gao ◽  
Junju Du ◽  
Aigen Li ◽  
...  

AbstractDuring October 2019 and March 2020, the luminous red supergiant Betelgeuse demonstrated an unusually deep minimum of its brightness. It became fainter by more than one magnitude and this is the most significant dimming observed in the recent decades. While the reason for the dimming is debated, pre-phase of supernova explosion, obscuring dust, or changes in the photosphere of the star were suggested scenarios. Here, we present spectroscopic studies of Betelgeuse using high-resolution and high signal-to-noise ratio near-infrared spectra obtained at Weihai Observatory on four epochs in 2020 covering the phases of during and after dimming. We show that the dimming episode is caused by the dropping of its effective temperature by at least 170 K on 2020 January 31, that can be attributed to the emergence of a large dark spot on the surface of the star.


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