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arXiv 0801.4829gr-qc
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奇异夸克双星螺旋上升的最后阶段

The final phase of inspiral of strange quark star binaries

Dorota Gondek-Rosinska, Francois Limousin

摘要:

本文计算了无旋奇异双星的最后螺旋相。在零温度下使用两种类型的状态方程-MIT袋模型和Dey等人1998年的奇异夸克物质模型。本文用多域谱方法研究了广义相对论的Isenberg-Wilson-Mathews近似中的预冷阶段。引力辐射驱动的双星系统的演化近似为一系列的准平衡位形在一个固定的重子数和减少分离。我们发现,最内层的稳定圆轨道(ISCO)总是由轨道不稳定的双星组成的两颗星主要是建立在独立的奇异夸克物质的总质量的一个二元系统和每个明星的紧凑性参数。相反,对于用重子状态方程描述的没有奇异相的中子星,ISCO由质量脱落极限给出。对于总质能大于$2 M_\odot$的等质量无旋奇异夸克星,在标志着螺旋相结束的ISCO处,引力波频率总是高于1.1kHz。我们发现,引力波的频率在ISCO上的紧凑性参数的等质量双星的依赖关系可以描述为相同的简单的分析公式,为广泛的质量独立的奇异星模型。详细的比较与二中子星模型,以及与三阶后牛顿点质量双星。对于两颗$1.35 M_\odot$奇异星,我们的数值结果与3 PN的相位差为内旋轨道的最后两个轨道的相位差为$\sim 40 %$。

英文摘要:

We present calculations of the final phase of inspiral of irrotational strange star binaries. Two types of equation of state at zero temperature are used - the MIT bag model and the Dey et al. 1998 model of strange quark matter. We study the precoalescence stage within the Isenberg-Wilson-Mathews approximation of General Relativity using a multidomain spectral method. The gravitational-radiation driven evolution of the binary system is approximated by a sequence of quasi-equilibrium configurations at a fixed baryon number and with decreasing separation. We find that the innermost stable circular orbit (ISCO) is determined always by an orbital instability for binaries consisting of two stars built predominantly of strange quark matter independently on the total mass of a binary system and compactness parameter of each star. In contrast, for neutron stars described by baryonic equation of state without exotic phases the ISCO is given by the mass-shedding limit. The gravitational wave frequency at the ISCO, which marks the end of the inspiral phase, is always higher than 1.1kHz for equal masses irrotational strange quark stars with the total mass-energy of a binary system greater than $2 M_\odot$. We find that the dependence of the frequency of gravitational waves at the ISCO on the compactness parameter for the equal mass binaries can be described by the same simple analytical formulae for broad ranges of masses independently on a strange star model. Detailed comparisons with binary neutrons star models, as well as with the third order Post-Newtonian point-mass binaries are given. The difference in the phase, for two $1.35 M_\odot$ strange stars, between our numerical results and 3PN is $\sim 40 %$ for the last two orbits of inspiral.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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