发表机构
Centro Brasileiro de Pesquisas Físicas; Instituto Tecnológico de Aeronáutica（巴西物理研究中心; 航空技术学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文提出含暗能量的中子星状态方程，发现增加暗能量比例使状态方程变软，能解释HESS J1731-347，并影响质量、半径、引力红移和振荡频率等性质。
AI 中文摘要
由Chaplygin暗流体构成的暗能量（DE）核心能够影响中子星（NSs）的多种可观测性质。然而，中子星也可能包含普通核物质与暗能量的混合物。在此视角下，我们提出了一种同时包含正常物质和暗能量的状态方程（EoS），其中自由参数$f$量化了暗能量密度相对于总能量密度的比例。正如预期，在极限$f \ ightarrow 0$下，我们恢复了对应于纯核物质的已知结果。值得注意的是，增加这一比例$f$会导致状态方程变软，从而强烈有利于满足因果性条件。根据我们的质量-半径结果，HESS J1731-347中的中心致密天体可以被满意地描述为一颗暗能量混合中子星。对于足够高的恒星质量，我们的计算进一步表明，引力红移和基本非径向振荡频率随着暗能量比例的增加而显著增大，而总引力质量和潮汐形变率则呈现相反趋势。与完全由普通物质组成的致密星的典型情况一致，我们发现，在我们的暗能量混合恒星模型中，最大质量构型对应的中心密度与径向振动频率平方消失的点重合。此外，更高的暗能量浓度导致这些构型的稳定性增强。
英文摘要
The presence of a dark energy (DE) core, made of a Chaplygin dark fluid, is capable of influencing the diverse observable properties of neutron stars (NSs). However, there is also the possibility that NSs could contain a mixture of ordinary nuclear matter and DE. In this perspective, we propose an equation of state (EoS) that includes both normal matter and DE, where a free parameter $f$ quantifies the ratio of DE density with respect to the total energy density. As expected, in the limit $f \rightarrow 0$ we recover the already known results corresponding to pure nuclear matter. Remarkably, increasing this fraction $f$ leads to a softer EoS and thus strongly favors the fulfillment of the causality condition. As a consequence of our mass--radius results, the central compact object in HESS J1731-347 can be satisfactorily described as a DE admixed NS. For sufficiently high stellar masses, our calculations further indicate that both the gravitational redshift and the fundamental nonradial oscillation frequency increase significantly with an increasing DE fraction, whereas the opposite trend is observed for the total gravitational mass and tidal deformability. As is typical for compact stars composed purely of ordinary matter, we find that in our DE admixed stellar models the central density corresponding to the maximum-mass configuration coincides with the point at which the squared radial vibration frequency vanishes. Moreover, higher DE concentrations lead to enhanced stability of these configurations.
Comments13 pages, 6 figures
