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arXiv 1406.0152gr-qc
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具有初始非均匀能量密度分布的辐射引力坍缩

Radiating Gravitational Collapse with an Initial Inhomogeneous Energy Density Distribution

G. Pinheiro, R. Chan

摘要:

提出了一种新的坍缩恒星模型,该模型由初始非均匀能量密度和各向异性压力流体组成,流体具有剪切、径向热流和向外辐射。在以前的论文中,我们中的一个总是假设初始恒星具有均匀的能量密度。本文的目的是通过引入初始非均匀能量密度来推广以前的模型,并将其与初始均匀能量密度坍塌模型进行比较。我们将展示这些模型在表征引力坍缩的所有物理量演化中的差异。分析了能量密度、压强、质量、光度和有效绝热指数的行为。在坍缩开始时,恒星的压力是各向同性的,但由于剪切的存在,压力变得越来越各向异性。这个黑洞从来没有形成过,因为视视界形成条件从来没有得到满足,这与之前的模型形成了一个黑洞相反。一个在无穷远处的观测者看到一个放射状的点源,它以指数方式辐射,直到达到最大亮度时,恒星突然熄灭。与前一个模型相反,在前一个模型中,光度也呈指数增长,达到最大值,然后下降,直到形成黑洞。有效绝热指数始终为正,没有任何间断,与前一个模型相反,在最大亮度附近有一个间断。这种坍缩比能量密度最初是均匀的情况慢约3000倍。

英文摘要:

A new model is proposed to a collapsing star consisting of an initial inhomogeneous energy density and anisotropic pressure fluid with shear, radial heat flow and outgoing radiation. In previous papers one of us has always assumed an initial star with homogeneous energy density. The aim of this work is to generalize the previous models by introducing an initial inhomogeneous energy density and compare it to the initial homogeneous energy density collapse model. We will show the differences between these models in the evolution of all physical quantities that characterizes the gravitational collapse. The behavior of the energy density, pressure, mass, luminosity and the effective adiabatic index is analyzed. The pressure of the star, at the beginning of the collapse, is isotropic but due to the presence of the shear the pressure becomes more and more anisotropic. The black hole is never formed because the apparent horizon formation condition is never satisfied, in contrast of the previous model where a black hole is formed. An observer at infinity sees a radial point source radiating exponentially until reaches the time of maximum luminosity and suddenly the star turns off. In contrast of the former model where the luminosity also increases exponentially, reaching a maximum and after it decreases until the formation of the black hole. The effective adiabatic index is always positive without any discontinuity in contrast of the former model where there is a discontinuity around the time of maximum luminosity. The collapse is about three thousand times slower than in the case where the energy density is initially homogeneous.

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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