基于相对论平均场理论的大质量原生中子星性质的研究

发布时间：2018-04-13 18:19

本文选题：宇宙粒子物理 + 致密核物质　；参考：《西南交通大学》2016年硕士论文

【摘要】：中子星是大质量恒星演化到末期,由于引力塌缩效应导致超新星爆发后残留核心形成的致密天体。中子星提供了远超过现有地球实验室所能达到的极端的密度、温度、磁场等物理条件,对了解物质结构层次有极其重要的作用,一直是天体物理、粒子物理和核物理等学科研究的重要对象和热点。特别是最近天文观测发现了2倍太阳质量的中子星,进一步推动了对中子星物质性质的深入研究。大质量中子星原生星的物质状态和性质不仅对中子星的形成和演化具有至关重要的影响,也对超新星爆发过程的模拟计算具有基本作用。本论文基于相对论平均场理论,对大质量原生中子星性质进行研究,主要完成了如下工作。首先对大质量中子星PSR J0348+0432的原生星性质进行了计算分析。选择相对论平均场理论中的合理参数组(核子耦合参数,超子耦合参数)描述了大质量中子星PSRJ0348+0432观测性质。将这些参数外推来描述PSR J0348+0432的原生星性质,得到了PSR J0348+0432的原生星的粒子组成、内部温度分布、状态方程和质量半径关系。结果发现原生星内部更容易出现超子,而且超子的出现降低了原生星内部的温度,软化状态方程,从而降低原生星的质量。第二、考虑引力修正效应对星体的影响,引进弱相互作用光矢U玻色子,讨论U玻色子对大质量中子星原生星的影响。发现U玻色子对压强和能量密度具有不同影响。在低密度处对压强的影响要比在高密度处明显,在高密度处对能量密度的影响比在低密度处明显。U玻色子会增大原生中子星的质量和半径,也会增大中子星原生星的转动惯量,同时减小引力红移效应。第三、计算分析熵效应对大质量中子星原生星性质的影响。对热密中子星物质,选取每重子熵从S=0到S=3变化,研究熵对大质量中子星PSR J1614-2230和PSRJ0348+0432前身星性质的影响。研究发现,熵使得状态方程变硬,熵值越大状态方程越硬,且熵对能量密度的影响和对压强的影响明显不同。熵会增加原生中子星的最大质量和半径,熵越大,对应的最大质量和半径越大。中子星原生星的转动惯量也随着熵的增加而增加；引力红移随着熵的增加而减小；温度将随着熵值的增加而增大。这些结果对中子星物理的理论研究具有重要参考价值。
[Abstract]:Neutron star is a dense body formed by the residual core after supernova burst due to gravitational collapse effect.Neutron stars provide extreme physical conditions such as density, temperature, magnetic field and so on that are far beyond the reach of existing Earth laboratories. They are extremely important in understanding the structure of matter and have always been astrophysics.Particle physics and nuclear physics and other disciplines of important objects and hot spots.In particular, recent astronomical observations have found a neutron star with twice the mass of the sun, which has further promoted the further study of the properties of the neutron star.The material state and properties of the primary star of a large mass neutron star not only have a vital impact on the formation and evolution of the neutron star, but also have a fundamental role in the simulation of the supernova burst process.Based on the relativistic mean field theory, the properties of mass primary neutron stars are studied in this paper.First, the properties of the primary star of the mass neutron star PSR J0348 0432 are calculated and analyzed.A reasonable set of parameters (nucleon coupling parameter, hyperon coupling parameter) in the relativistic mean field theory is chosen to describe the observed properties of the mass neutron star PSRJ0348 0432.These parameters are extrapolated to describe the primary star properties of PSR J0348 0432. The particle composition, internal temperature distribution, equation of state and mass radius of PSR J0348 0432 are obtained.The results show that the hyperons are more likely to appear in the primary star, and the appearance of the hyperons reduces the internal temperature of the primary star and softens the equation of state, thus reducing the mass of the primary star.Secondly, considering the influence of gravitational correction effect on stars, we introduce the weakly interacting light vector U bosons, and discuss the influence of U bosons on the primary stars of large mass neutron stars.It is found that U bosons have different effects on pressure and energy density.The effect on pressure at low density is more obvious than that at high density, and the effect on energy density at high density is more obvious than at low density. U boson increases the mass and radius of the primary neutron star, and also increases the moment of inertia of the primary star.At the same time, the gravitational redshift effect is reduced.Thirdly, the effect of entropy effect on the properties of primary star of mass neutron star is calculated and analyzed.The effects of entropy on the properties of PSR J1614-2230 and PSRJ0348 0432 precursor stars are studied by selecting the variation of entropy per baryon from S ~ (0) to S ~ (3) for thermal neutron stars.It is found that entropy harden the equation of state, the larger the entropy value is, the harder the equation of state is, and the effect of entropy on energy density is obviously different from that on pressure.Entropy increases the maximum mass and radius of the primary neutron star, and the larger the entropy, the larger the corresponding maximum mass and radius.The moment of inertia of the primary star increases with the increase of entropy, the redshift of gravity decreases with the increase of entropy, and the temperature increases with the increase of entropy.These results have important reference value for the theoretical study of neutron star physics.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P145.6

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