论文标题

在压力各向异性存在下,托尔曼时空的紧凑型恒星模型

Compact stellar model in Tolman space-time in presence of pressure anisotropy

论文作者

Bhar, Piyali, Das, Shyam, Parida, Bikram Keshari

论文摘要

在本文中,我们为球形对称的各向异性物质分布开发了一种新的相对论紧凑型恒星模型。该模型是通过通过调用Tolman {\ em ansatz}的指标势之一$ g_ {rr} $的托尔曼{\ em ansatz}来获得新的解决方案获得的。我们已经将获得的内部溶液与紧凑型恒星的边界表面上的Schwarzschild外部空间匹配。这些匹配条件以及消除跨恒星边界的径向压力的条件已被用来确定模型参数。我们已经表明,恒星的中心压力取决于参数$ P_0 $。我们使用紧凑型星4U 1608-52和Vela X-1的最新数据估计了$ P_0 $的范围。还讨论了$ p_0 $对不同物理参数的影响,例如压力各向异性,声音的潜意识速度,相对论绝热指数等。精心进行了分析和图形讨论的紧凑型星的开发模型,以证明其满足所有标准需要逼真的恒星。从我们的分析中,我们已经证明,各向异性的效果对于$ p_0 $的较高值变得很小。质量 - 拉迪乌斯(M-R)关系表明,在我们的模型中也研究了给定表面密度的观察到的脉冲星的最大质量。此外,已经显示了半径和质量与中央密度的变化,这使我们能够估计紧凑型恒星给定半径(或质量)的中心密度。

In this paper, we develop a new relativistic compact stellar model for a spherically symmetric anisotropic matter distribution. The model has been obtained through generating a new class of solutions by invoking the Tolman {\em ansatz} for one of the metric potentials $g_{rr}$ and a physically reasonable selective profile of radial pressure. We have matched our obtained interior solution to the Schwarzschild exterior spacetime over the bounding surface of the compact star. These matching conditions together with the condition of vanishing the radial pressure across the boundary of the star have been utilized to determine the model parameters. We have shown that the central pressure of the star depends on the parameter $p_0$. We have estimated the range of $p_0$ by using the recent data of compact stars 4U 1608-52 and Vela X-1. The effect of $p_0$ on different physical parameters e.g., pressure anisotropy, the subliminal velocity of sound, relativistic adiabatic index etc. have also been discussed. The developed model of the compact star is elaborately discussed both analytically and graphically to justify that it satisfies all the criteria demanded a realistic star. From our analysis, we have shown that the effect of anisotropy becomes small for higher values of $p_0$. The mass-radius (M-R) relationship which indicates the maximum mass admissible for observed pulsars for a given surface density has also been investigated in our model. Moreover, the variation of radius and mass with central density has been shown which allow us to estimate central density for a given radius (or mass) of a compact star.

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