检索结果-南通市图书馆

Electrically charged: An effective mechanism for soft EOS supporting massive neutron star

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2015年第10期58卷 100-106页

作者： JING ZhenZhen WEN DeHua ZHANG XiangDong School of Sciences South China University of Technology

The massive neutron star discoverer announced that strange particles, such as hyperons should be ruled out in the neutron star core as the soft Equation of State(EOS) can-not support a massive neutron star. However, many of the nuclear theories and laboratory experiments support that at high density the strange particles will appear and the corresponding EOS of super-dense matters will become soft. This situation promotes a challenge between the astro-observation and nuclear physics. In this work, we introduce an effective mechanism to answer this challenge, that is, if a neutron star is electrically charged, a soft EOS will be equivalently stiffened and thus can support a massive neutron star. By employing a representative soft EOS, it is found that in order to obtain an evident effect on the EOS and thus increasing the maximum stellar mass by the electrostatic field, the total net charge should be in an order of 1020 C. Moreover, by comparing the results of two kind of charge distributions, it is found that even for different distributions, a similar total charge:～2.3×1020C is needed to support a～2.0M⊙neutron star.

关键词： neutron star equation of state electrical field

Impact of neutron star crust on gravitational waves from the axial w-modes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第6期20卷 58-63页

作者：文德华付宏洋陈伟 Department of Physics South China University of Technology Department of Physics Jinan University

The imprints of the neutron star crust on the gravitational waves emitted from the axial w-modes are investigated by adopting two typical equations of state （EOSs） of the crust matter and two representative EOSs of the core matter. It is shown that there is a significant effect of the crust EOSs on the gravitational waves from the axial w-mode oscillation for a stiff core EOS.

关键词： equation of state neutron star gravitational waves

Constraints on the kinetic energy of type-Ic supernova explosion from young PSR J1906+0746 in a double neutron star candidate

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2021年第6期30卷 721-726页

作者： Yi-Yan Yang Cheng-Min Zhang Jian-Wei Zhang De-Hua Wang School of Physics and Electronic Sciences Guizhou Education UniversityGuiyang 550018China CAS Key Laboratory of FAST National Astronomical ObservatoriesChinese Academy of Sciences(CAS)Beijing 100012China Astronomy Department Beijing Normal UniversityBeijing 100875China School of Physics and Electronic Sciences Guizhou Normal UniversityGuiyang 550001China

So far among the nineteen pairs of detected double neutron star(DNS) systems, it is a usual fact that the first-born recycled pulsar is detected, however the youngest DNS system PSR J1906+0746, with the characteristic age of 113 kyr, is one of the three detected DNS as a non-recycled and second-born NS, which is believed to be formed by an electron capture or a low energy ultra-stripped iron core-collapse supernova(SN) explosion. The SN remnant around PSR J1906+0746 is too dim to be observed by optical telescopes, then its x-ray flux limit has been given by Chandra. A reference pulsar PSR J1509-5850 with the young characteristic age of 154 kyr was chosen as an object of comparison, which has an SN remnant observed by Chandra and is believed to be formed by iron core SN explosion. We impose a restriction on the maximum kinetic energy of electron-capture(EC) SN explosion that induces the formation of PSR J1906+0746. The estimated result is(4–8)×10^(50) erg(1 erg= 10-7 J), which is consistent with that of the published simulations of the EC process, i.e., a lower value than that of the conventional iron core SN explosion of(1–2)×10^(51) erg. As suggested, EC process for NS formation is pertained to the subluminous type Ic SN by the helium star with ONeMg core, thus for the first time we derived the kinetic energy of EC SN explosion of DNS, which may be reconciled with the recent observation of type Ic SN 2014 ft with kinetic energy of 2 × 10^(50) erg.

关键词： neutron star pulsar astrophysics high energy astrophysical phenomena

Metric of the gravitational field outside the neutron star

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2001年第6期44卷 801-806页

作者：王永久唐智明 Institute of Physics Hunan Normal University Changsha 410081 China

We have obtained the solution of the Einstein equation and the electric-magnetic field outside the neutron star, and at the same time, we investigated their asymptotic properties.

关键词： neutron star generation technique theorem gravitational field.

The Effects of δ Meson on the neutron star Cooling

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2012年第5期14卷 375-378页

作者：许妍刘广洲吴姚睿朱明枫喻孜王红岩赵恩广 Center for Theoretical Physics Jilin University College of Science Nanjing Forestry University Institute of Theoretical Physics Chinese Academy of Sciences

In the framework of the relativistic mean field theory, the isovector scalar interaction is considered by exchanging δ meson to study the influence of δ meson on the cooling properties of neutron star matter. The calculation results show that with the inclusion of δ meson, the neutrino emissivity of the direct Urca processes increases, and thus enhances the cooling of neutron star matter. When strong proton superfluidity is considered, the theoretical cooling curves agree with the observed thermal radiation for isolated neutron stars.

关键词： neutron star direct Urca processes δ meson proton superfluidity

R-mode Instability of neutron star with Non-Newtonian Gravity

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2013年第1期59卷 47-52页

作者：燕晶文得华 Department of Physics South China University of Technology

The Chandrasekhar-Friedmann-Schutz （CFS） instabilities of r-modes for canonical neutron stars （1.4 Me） with rigid crusts are investigated by using an equation of state of asymmetric nuclear matter with super-soft symmetry energy, where the non-Newtonian gravity proposed in the grand unification theories is also considered. Constrained by the observations of the masses and the spin frequencies for neutron stars, the boundary of the r-mode instability window for a canonical neutron star is obtained, and the results show that the observed neutron stars are all outside the instability window, which is consistent with the theoretical expectation. In addition, an upper limit of the non-Newtonian gravity parameters is also given.

关键词： neutron star r-mode non-Newtonian gravity

Direct Urca Processes Involving Proton ^1S0 Superfluidity in neutron star Cooling

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2018年第4期69卷 425-433页

作者： Yan Xu Zi Yu Xiao-Jun Zhang Cun-Bo Fan Guang-Zhou Liu En-Guang Zhao Xiu-Lin Huang Cheng-Zhi Liu Changchun Observatory National Astronomical Observatories CAS Changchun 130117 China College of Science Nanjing Forestry University Nanjing 210037 China Center for Theoretical Physics Jilin University Changchun 130023 China Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China

A detailed description of the baryon direct Urca processes A: n → p + e + ν_e, B: Λ→ p + e + ν_e and C: Ξ^-→Λ + e + ν_e related to the neutron star cooling is given in the relativistic mean field approximation. The contributions of the reactions B and C on the neutrino luminosity are calculated by means of the relativistic expressions of the neutrino energy losses. Our results show that the total neutrino luminosities of the reactions A, B and C within the mass range(1.603–2.067) M_⊙((1.515–1.840) M_⊙ for TM1 model) for GM1 model are larger than the corresponding values for neutron star without hyperons. Furthermore, although the neutrino emissivity of the reaction A is suppressed with the appearance of the proton ~1S_0 superfluid, the contribution of the reactions B and C can still quicken a massive neutron star cooling. In particular, the reaction C in PSR J1614-2230 and J0348+0432 is not suppressed by the proton ~1S_0 superfluid due to the higher threshold density of the reaction C, which will further speed up the two pulsars cooling.

关键词： neutron star the proton ^1S0 superfluid

Effect of Mesons f0（975） and Ф（1020） and Variety of UΞ^（N） on Properties of neutron star Matter

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2004年第3期41卷 441-446页

作者： TANYu-Hong SUNBao-Xi LILei NINGPing-Zhi TheoreticalPhysicsDivision NankaiInstituteofMathematicsNankaiUniversityTianjin300071China InstituteofHighEnergyPhysics theChineseAcadcmyofSciencesBeijing100039China DepartmentofPhysicsNankaiUniversity Tianjin300071China

We examine the effect of adding mesons fo(975)and φ(1020)as well as the variety of U(the potential well depth ofin nuclear matter)from -10 MeV to -28 MeV on the extent of the particles participation and the properties of the neutron star in the relativistic mean field *** find that considering the contribution of fo and φ mesons,the equation of state of the neutron star turns soft,the maximum mass reduces while the corresponding radius *** appear at lower density as Ubecomes deeper,and the variety of Uhas little effect on the equation of state and the properties of the neutron star.

关键词： neutron star equation of state

On the moment of inertia of a proto neutron star

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2010年第10期34卷 1587-1592页

作者：赵先锋张华贾焕玉 Department of Electronics Engineering Chuzhou University Institute of Applied Physics and Computational Mathematics Institute for Modern Physics Southwest Jiaotong University

The influences of σ^＊ and Ф mesons, temperature and coupling constants of nucleons on the moment of inertia of the proto neutron star （PNS） are examined in the framework of relativistic mean field theory for the baryon octet {n, p, A, ∑^-, ∑^,∑^＋,^-, ^0} system. It is found that, compared with that without considering σ^＊ and Ф mesons, the moment of inertia decreases. It is also found that the higher the temperature, the larger the incompressibility and symmetry energy coefficient, and the larger the moment of inertia of a PNS. The influence of temperature and coupling constants of the nucleons on the moment of inertia of a PNS is larger than that of the σ^＊ and Ф mesons.

关键词： neutron star moment of inertia relativistic mean field theory