超新星核中的非奇异—奇异夸克物质相变

最近Ｇｅｎｔｉｌｅ等研究了超新星核区从核物质到夸克物质的一级相变，沿着他们的工作，本文研究从两味夸克物质到三味夸克物质的相变过程，我们发现相变时标小于１０＾－７秒，超新星的中心温度和核区的中微子总能量明显增大，这不仅会增加超新星爆发的成功机会，而且会提高复活激波的能量，同时会影响新生中子星的冷却，核区存在Ｓｃｈｗａｒｚｓｃｈｉｌｄ对流。     

奇异夸克相变对Ⅱ型超新星激波能量的影响

在模拟超新星演化时,考虑非奇异一奇异夸克相变因素,与没有考虑奇异相变的情况相比,得到了更强的激波．这可能是奇异相变增加了星核区对流不稳定性所致在本文的计算环境里,一阶奇异夸克相变的结果使具有128MO铁星核的WW（88）模型爆发,打破了瞬发机制只能使约1．1MO铁星核模型爆发的上限,并支持了戴子高等人所作出的奇异夸克相变能提高超新星爆发机会的论断．     

奇异夸克相变对II型超新星激波能量的影响

在模拟超新星演化时,考虑非奇异－奇异夸克相变因素,与没有考虑奇异相变的情况相比,得到了更强的激波,这可能是奇异相变增加了星核区对流不稳定性所致,在本的计算环境里,一阶奇异夸克相变的结果使具有１．２８Ｍ铁星核的ＷＷ（８８）模型爆发,打破了瞬发机制只能使约１．１Ｍ铁星核模型爆发的上限,并支持了戴子高等人所作出的奇异夸克相变能超新爆发机会的论断。     

奇异夸克相变对II型超新星激波能量的影响

在模拟超新星演化时, 考虑非奇异奇异夸克相变因素,与没有考虑奇异相变的情况相比, 得到了更强的激波.这可能是奇异相变增加了星核区对流不稳定性所致. 在本文的计算环境里,一阶奇异夸克相变的结果使具有1.28 M铁星核的WW(88)模型爆发,打破了瞬发机制只能使约1.1 M铁星核模型爆发的上限,并支持了戴子高等人所作出的奇异夸克相变能提高超新星爆发机会的论断.     

夸克相变对Ⅱ型超新星转移能量的影响

假设超新星在坍缩过程中,当物质达到超核密度状态后,在临界密度下发生夸克相交．用ＷＷ（８８）初始模型在有夸克相交情形下对坍缩反弹和激波传播作了模拟,重点讨论了夸克相变对转移能量的影响．在适当的临界密度下发生夸克相交,可以增加转移能量从而得到更强的激波．     

轻夸克物质团、奇异子和致密矮星

相对于核物质和奇异夸克物质, 仅由两味夸克构成的轻夸克物质(即ud夸克物质)有可能更稳定. 而对于由这三类物质构成的典型物质集团, 研究发现如果ud夸克物质具有较大的对称能, 那么其物质团会在特定大小(重子数$A\approx1000$)时最稳定. 在这种情况下, 就可能存在由ud夸克物质团和电子构成的致密矮星, 即ud夸克矮星. 通过进一步研究这类ud夸克矮星的结构可知: 相较于传统的由原子核和电子构成的白矮星, ud夸克矮星通常具有较小的半径, 而被正常物质覆盖的ud夸克矮星的半径则在它们之间, 这与最近观测到的质量和半径都异常小的白矮星相符.     

夸克相变对Ⅱ型超新星转移能量的影响

假设超新星在坍缩过程中,当物质达到超核密度状态后,在临界密度下发生夸克相变。用ＷＷ（８８）初始模型在有夸克相变情形下对坍缩反弹和激波传播作了模拟,重点讨论了夸克相变对转移能量的影响,在适当的临界密度下发生夸克相变,可以增加转移能量从而得到更强的激波。     

宇宙线与奇异滴

奇异滴，即质量较小的奇异夸克物质团块，有关它的研究涉及物理学的多个重要分支．如果存在奇异滴，人们对暗物质组分和致密星体结构的认识将会改变，强相互作用的研究也会有新的途径．已经有若干实验结果表明宇宙线中可能含有奇异滴成分．因此，研究宇宙线奇异滴的产生、传播及其与地球大气作用过程等是非常重要的．将重点围绕上述几个问题，综述目前奇异滴研究的现状。     

强作用对奇异星观测效应的影响

奇异星是类似于中子星的曲奇异夸克物质组成的致密天体。本文研究了夸克这间的强作用对奇异星观测效应的影响。我们认为：（１）中子星转变为奇异星的行为是一种大的周期突变（ｇｌｉｔｃｈ）现象，这种现象取决于夸克间的强作用；（２）强作用使高温奇异星的振动阻尼也有效，这可能是驱动超新星爆发的新机制；（３）强作用加强了高温情形下奇异星和中子星在转动上的差别，奇异星的最小周期比中子星的小。     

超新星在旋涡星系中的径向分布

本文研究了在１９９３年３月２８日之前发现的８９９颗超新星（ＳＮｅ）的样本。其中２７７颗ＳＮｅ被用来研究超新星在其母星系中的径向分布。我们研究了四个星系样本中超新星在产生单个超新星（称为一般超新星）的星系及在产生多个超新星（称为多重超新星）的星系中的径向分布。这四个星系样本为：总旋涡星系样本，Ｓｂ￣Ｓｂｃ星系样本，Ｓｃ星系样本，Ｓｃ￣Ｓｄ星系样本。研究的结果表明：多重超新星比一般超新星在其母星系中具     

Neutron Stars with a Quark Core. I. Equations of State

An extensive set of realistic equations of state for superdense matter with a quark phase transition is derived on the basis of the three equations of state for neutron matter and the eight variants of strange quark-gluon plasmas in the MIT quark bag model. The characteristics of the phase transitions are described and the calculated equations of state with a density jump are studied in detail.     

早期中子星和夸克物质

夸克禁闭的解除与夸克物质的存在一直是物理学家极感兴趣的问题。尽管理论上已指出在超高温或超高密的条件下可以有夸克物质存在,但是由于地面实验室的条件所限,目前还不能通过实验证实这一点.宇宙中被观测到的中子星(例如crab和Vela脉冲星)的中心密度大于4倍的核物质密度,其中心温度也可以达到10~8—10~9K,于是人们希     

The phase transitions of superdense matter and supernova explosions

Effects of the phase transitions of superdense matter on supernova explosions are investigated with the aid of an idealized equation of state on the assumptions of adiabatic collapse. It is found that in the case of strong phase transitions explosions become weaker, while in the case of weak phase transitions explosions become stronger. However, the increment of the ejected energy is not so large as suggested by Migdalet al. (1979).Paper presented at the IAU Third Asian-Pacific Regional Meeting, held in Kyoto, Japan, between 30 September–6 October, 1984.     

Neutron star mergers in the context of the hadron–quark phase transition

The long awaited event of the detection of a gravitational wave from a binary neutron star merger and its electromagnetic counterparts marked the beginning of a new era in observational astrophysics. The brand-new field of gravitational wave astronomy combined with multi-messenger observations will uncover violent, highly energetic astrophysical events that could not be explored before by humankind. This article focuses on the presumable appearance of a hadron–quark phase transition and the formation of regions of deconfined quark matter in the interior of a neutron star merger product. The evolution of density and temperature profiles inside the inner region of the produced hypermassive/supramassive neutron star advises an incorporation of a hadron–quark phase transition in the equation of state of neutron star matter. The highly densed and hot neutron star matter of the remnant populate regions in the QCD phase diagram where a non neglectable amount of deconfined quark matter is expected to be present. If a strong hadron–quark phase transition would happen during the post-merger phase, it will be imprinted in the spectral properties of the emitted gravitational wave signal and might give an additional contribution to the dynamically emitted outflow of mass.     

Neutron Stars with a Quark Core. II. Basic Integral and Structural Parameters

A broad sample of computed realistic equations of state of superdense matter with a quark phase transition is used to construct a series of models of neutron stars with a strange quark core. The integral characteristics of the stellar configurations are obtained: gravitational mass, rest mass, radius, relativistic moment of inertia, and red shift from the star's surface, as well as the mass and radius of the quark core within the allowable range of values for the central pressure. The parameters of some of the characteristic configurations of the calculated series are also given and these are studied in detail. It is found that a new additional region of stability for neutron stars with strange quark cores may exist for some models of the equation of state.     

Strange quark matter in a strong magnetic field

The stability of strange quark matter in the presence of a strong magnetic field is investigated using a dynamical, density dependent, quark mass approach to confinement. Changes in both the single particle and bulk energies of a system which are due to the strong magnetic field are also calculated. It is shown that the presence of a magnetic field makes strange quark matter energetically more stable.     

The effect of strange quark transition on the shock energy of Type-II supernovae

We have found that the introduction of strange quark phase transition in the simulation of the evolution of supernovae results in a stronger shock wave. This is probably due to an increased convective instability in the core. For our range of calculation we found that a first-order strange phase transition can induce explosion in a WW(88) model with a 1.28 M iron core (the upper bound for prompt explosion was about 1.1 M). Our result supports DAI Zi-gao et al.'s thesis that strange quark phase transition can raise the probability of supernova explosion.     

Maximum mass of a hot neutron star with a quark core

We have considered a hot neutron star with a quark core,a mixed phase of quark-hadron matter,and a hadronic matter crust and have determined the equation of state of the hadronic phase and the quark phase.We have then found the equation of state of the mixed phase under the Gibbs conditions.Finally,we have computed the structure of a hot neutron star with a quark core and compared our results with those of the neutron star without a quark core.For the quark matter calculations,we have used the MIT bag model...     

Thermal evolution of rotating hybrid stars

As a neutron star spins down, the nuclear matter is continuously converted into quark matter due to the core density increase, and then latent heat is released. We have investigated the thermal evolution of neutron stars undergoing such deconfinement phase transition. We have taken into account the conversion in the frame of the general theory of relativity. The released energy has been estimated as a function of changed rate of deconfinement baryon number. The numerical solutions to the cooling equation are seen to be very different from those without the heating effect. The results show that neutron stars may be heated to higher temperatures which is well matched with pulsar's data despite the onset of fast cooling in neutron stars with quark matter cores. It is also found that the heating effect has a magnetic field strength dependence. This feature could be particularly interesting for high temperatures of low-field millisecond pulsars at a later stage. The high temperature could fit the observed temperature for PSR J0437−4715.