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在相对论平均场理论框架内,利用Λ超子的结合能和中子星质量的观测数据得到超子标量介子耦合参数χσ的范围是0.33—0.77。在这个范围内, 研究了χσ取不同值时, 包含核子, Λ和Ξ超子的热前中子星(固定单个重子熵s=1)的性质。结果表明, 如果超子耦合参数变大, 前中子星核心温度变高, 中微子丰度变低, 前中子星的亚稳态质量范围变小。如果χσ超过了0.75, 前中子星不可能演变成黑洞。联系SN1987A讨论了这一结果的意义。In the framework of the relativistic mean field theory(RMFT), protoneutron stars with hyperons are studied. To be compatible with neutron star masses, the hyperon scalar coupling χσ should lie in the range of 0.33—0.77. As the hyperon scalar coupling increases, in protoneutron star matter, the core temperature increases whereas the abundance of neutrinos decreases. The metastable mass range of protoneutron stars narrows as the temperature increases. It is found that a protoneutron star cannot subside into a low mass black hole when χσ>0.75. Furthermore, the case of SN1987A is discussed. 相似文献
174.
ZHANG Jie LIU Men-Quan LUO Zhi-Quan 《理论物理通讯》2007,47(4):765-768
Based on shell model of nuclei, the influence of a high magnetic field on β^+ decay in the crusts of accreting neutron stars is analyzed. The magnetic field effect on 54 Mn is discussed. The results show that a weak magnetic field makes little effect on β^+ decay but a strong magnetic field (B 〉 10^11 G) improves β^+ decay rates obviously. The conclusion derived will benefit to develop further research on nuclear astrophysics in the future. 相似文献
175.
High energy astrophysics is one of the most active branches in the contemporary astrophysics. It studies astrophysical objects that emit X-ray and γ-ray photons, such as accreting super-massive and stellar-size black holes, and various species of neutron stars. With the operations of many space-borne and ground-based observational facilities, high energy astrophysics has enjoyed rapid development in the past decades. It is foreseen that the field will continue to advance rapidly in the coming decade, with possible ground-breaking discoveries of astrophysical sources in the high-energy neutrino and gravitational wave channels. This Special Issue of Frontiers of Physics is dedicated to a systematic survey of the field of high energy astrophysics as it stands in 2013. 相似文献
176.
在相对论平均场理论(RMFT)框架内,使用GL91参数组结合超核数据和大质量中子星的观测数据限定超子标量耦合参数Xσ=0.59~1.0,用慢转近似计算了大质量中子星和前中子星的转动惯量。当Xσ从0.59增加到1.0,中子星(前中子星)的最大转动惯量增幅达89%(60%)。在同样的变化范围内,用Crab的观测数据,计算得到中子星(前中子星)的最大能量损失(dE/dt)的增幅为44%(25%),最大磁场增幅为48%(38%)。相比于前中子星,中子星的性质对超子参数更为敏感。当Xσ从0.59增加到1.0,PSR J0348+0432的转动惯量和dE/dt的增幅均为14%,而磁场减幅为10%。如果天文观测能够给出中子星转动惯量的上限,或者同时精确测量中子星的质量和转动惯量,能帮助人们进一步限定超子参数。In the framework of the relativistic mean field theory(RMFT) with GL91 cets, the momentum of inertia (I) of slowly rotating neutron stars is studied by perturbative approach. The scalar hyperon coupling should lie in the range of Xσ=0.59~1.0 to be compatible with massive neutron stars. As Xσ increases from 0.59 to 1.0, the maximum momentum of inertia(Imax) of neutron (protoneutron) stars increases by 89% (60%). According to the data of Crab, the maximum energy loss(dE/dt) of neutron (protoneutron) stars will increase by 44%(25%)and the maximum magnetic field (B) will increase by 48%(38%). I and dE/dt of PSR J0348+0432 both increase by 14%, while B decreases by 10% as Xσ increases from 0.59 to 1.0. So if the upper bound of I, or the accurate values of both the mass and I of neutron stars could be provided by the astronomical observations, the hyperon couplings should be further constrained in the future. 相似文献
177.
In the various models,we study the influences of the softness of nuclear matter,the vacuum fluctuation of nucleons and σ mesons on the production of strange particles in neutron stars,We find that the stiffer the nuclear matter is,the more easily the strange particles is produced in neutron stars.The vacuum fluctuation of nucleons has large effect on strange particle production while that of σ meson has little effect on it. 相似文献
178.
179.
We study the neutron star composition in the presence of a strong magnetic field. The effects of the anomalousmagnetic moments of both nucleons and electrons are investigated in relativistic mean field calculations for afl-equilibrium system. Since neutrons are fully spin polarized in a large field, generally speaking, the protonfraction can never exceed the field free case. An extremely strong magnetic field may lead to a pure neutronmatter instead of a proton-rich matter. 相似文献