中子星的结构与冷却
发布时间：2018-11-21 11:28
【摘要】：由于核物理理论的不确定性,在中子星的能标下可以出现各种可能的自由度。对于不同的物质相或者不同的相互作用模型,将其状态方程代入广义相对论框架下的恒星结构方程,就能求解出不同的质量半径关系,从而可以利用观测对状态方程进行限制。另一方面,对于不同的微观组成来说,其系统内部的动力学过程也不尽相同,这些差异可能会在宏观尺度上通过中子星的热辐射性质体现出来。因此,我们若将中子星冷却理论与热辐射数据进行对比,也可以得知星体内部物质的信息。 正因为存在年龄老但温度高的脉冲星,在研究晚期的中子星冷却时,我们不能不考虑加热机制的影响。化学加热就是其中一种对晚期中子星热演化有较大贡献的机制,它起源于星体因为转动压缩而导致的系统化学平衡的偏离。由于弛豫时标比转动压缩的时标要长,系统偏离之后就再也回不到平衡态,这便有了化学能的储存与耗散加热的竞争过程,最终使得中子星的温度会回升到一个准平衡态。 在此基础上,本文讨论了含有强子夸克混合相的中子星在转动压缩时发生退禁闭相变的情况。对于这种情况,内部的强子物质会转化成更稳定的夸克物质,并间接导致物质组分的变化,同样的,这也会引起化学平衡的偏离与耗散加热。考虑了星体内部的物质分布与转动结构之后,我们发现,退禁闭相变的出现使得化学加热效率有了明显的提高,且对于高磁场的中子星来说也是可以有加热效果的。 考虑到演化过程中的化学能不仅是通过反应被耗散成了可以加热星体的内能,还有一部分会被非平衡Urca反应产生的中微子直接辐射掉,本文也对化学能的耗散机制做了讨论。通过计算发现,新的耗散机制对中子星的冷却曲线影响不大。
[Abstract]:Due to the uncertainty of nuclear physics theory, various possible degrees of freedom can appear under the energy scale of neutron stars. For different material phases or different interaction models, the equation of state can be substituted into the stellar structure equation under the framework of general relativity, and different mass radii can be solved, thus the state equation can be restricted by observation. On the other hand, for different microscopic compositions, the dynamic processes within the system are different, and these differences may be reflected by the thermal radiation properties of neutron stars on a macro scale. Therefore, if we compare the neutron star cooling theory with the thermal radiation data, we can also know the information of the matter inside the star. Because of the existence of pulsars of high temperature, the influence of heating mechanism should be taken into account in the study of the cooling of neutron stars in the late stage. Chemical heating is one of the major contributions to the thermal evolution of late neutron stars, which originates from the deviation of the chemical equilibrium of the system caused by the rotational compression of stars. Because the relaxation time scale is longer than the time scale of rotational squeezing, the equilibrium state can not be returned to the system after the system deviates, which leads to the competitive process of chemical energy storage and dissipative heating, and finally the temperature of the neutron star will rise to a quasi-equilibrium state. On the basis of this, the deblocking phase transition of neutron stars with Hadron quark mixed phase during rotational compression is discussed. In this case, the internal Hadron matter will be converted into more stable quark matter, and indirectly lead to the change of the composition of the matter. Similarly, this will lead to the deviation of the chemical equilibrium and dissipative heating. Considering the distribution of matter and the rotational structure of the stars, we find that the appearance of the deconfined phase transition can obviously improve the chemical heating efficiency, and it can also be used to heat the neutron stars with high magnetic field. Considering that the chemical energy in the evolution process is not only dissipated to the inner energy of the star by reaction, but also a part of the neutrino radiation produced by the nonequilibrium Urca reaction, the dissipative mechanism of the chemical energy is also discussed in this paper. It is found that the new dissipative mechanism has little effect on the cooling curve of neutron stars.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：P145.6
[Abstract]:Due to the uncertainty of nuclear physics theory, various possible degrees of freedom can appear under the energy scale of neutron stars. For different material phases or different interaction models, the equation of state can be substituted into the stellar structure equation under the framework of general relativity, and different mass radii can be solved, thus the state equation can be restricted by observation. On the other hand, for different microscopic compositions, the dynamic processes within the system are different, and these differences may be reflected by the thermal radiation properties of neutron stars on a macro scale. Therefore, if we compare the neutron star cooling theory with the thermal radiation data, we can also know the information of the matter inside the star. Because of the existence of pulsars of high temperature, the influence of heating mechanism should be taken into account in the study of the cooling of neutron stars in the late stage. Chemical heating is one of the major contributions to the thermal evolution of late neutron stars, which originates from the deviation of the chemical equilibrium of the system caused by the rotational compression of stars. Because the relaxation time scale is longer than the time scale of rotational squeezing, the equilibrium state can not be returned to the system after the system deviates, which leads to the competitive process of chemical energy storage and dissipative heating, and finally the temperature of the neutron star will rise to a quasi-equilibrium state. On the basis of this, the deblocking phase transition of neutron stars with Hadron quark mixed phase during rotational compression is discussed. In this case, the internal Hadron matter will be converted into more stable quark matter, and indirectly lead to the change of the composition of the matter. Similarly, this will lead to the deviation of the chemical equilibrium and dissipative heating. Considering the distribution of matter and the rotational structure of the stars, we find that the appearance of the deconfined phase transition can obviously improve the chemical heating efficiency, and it can also be used to heat the neutron stars with high magnetic field. Considering that the chemical energy in the evolution process is not only dissipated to the inner energy of the star by reaction, but also a part of the neutrino radiation produced by the nonequilibrium Urca reaction, the dissipative mechanism of the chemical energy is also discussed in this paper. It is found that the new dissipative mechanism has little effect on the cooling curve of neutron stars.
【学位授予单位】：华中师范大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：P145.6
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