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arXiv 2005.02750gr-qcastro-ph.HE
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拓扑中子星的稳定性

Stability of topological neutron stars

Daniela D. Doneva, Stoytcho S. Yazadjiev, Kostas D. Kokkotas

摘要:

张量多标量理论(TMST)是爱因斯坦理论最自然的推广之一,它们在数学上是自洽的,没有病态。它们通过了所有已知的观测,但与标准的标量张量理论相反,TMST提供了极其丰富的解谱,并允许与广义相对论有很大的偏差。在这些理论中,拓扑中子星是最有趣的对象之一。本文的主要目标是研究它们的径向稳定性,因为即使对于固定的拓扑荷值,也可以存在许多解的分支。事实证明,对于每个拓扑荷值,只有一个分支是稳定的,而所有其他分支都是不稳定的。稳定的分支正好是从小到大的中子星质量的一个分支,其半径值也与观测结果一致。正如预期的那样,它在质量最大时变得不稳定。研究了径向模的频率,发现在大多数情况下,径向模的频率大于广义相对论模的频率,并且随着拓扑荷的增加而增加。所有这些都表明,拓扑中子星是可行的天体物理对象,应进一步探索,以确定其观测表现。

英文摘要:

Tensor-multi-scalar theories (TMST) are among the most natural generalizations of Einstein's theory, they are mathematically self-consistent and free from pathologies. They pass through all the known observations but contrary to standard scalar-tensor theories, TMST offer extremely rich spectrum of solutions and allow for large deviations from general relativity. One of the most interesting objects in these theories are the topological neutron stars. The main goal in the present paper is to study their radial stability since many branches of solutions can exist even for a fixed value of the topological charge. It turns out that only one of these branches is stable for each value of the topological charge while all the rest are unstable. The stable branch is exactly the one that spans from small to large neutron star masses having as well moderate values of the radii in agreement with the observations. As expected, it becomes unstable at the maximum of the mass. The frequencies of the radial modes are examined and it turns out that in most cases the mode frequencies are larger than the general relativistic ones and they increase with the increase of the topological charge. All this shows that the topological neutron stars are viable astrophysical objects that should be explored further in order to determine their observational manifestations.

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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