Despite their long history and astrophysical importance, some of the key properties of neutron stars are still uncertain. The extreme conditions encountered in their interiors, involving matter of uncertain composition at extreme density and isospin asymmetry, uniquely determine the stars' macroscopic properties within General Relativity. Astrophysical constraints on those macroscopic properties, such as neutron star masses and radii, have long been used to understand the microscopic properties of the matter that forms them. In this article we discuss another astrophysically observable macroscopic property of neutron stars that can be used to study their interiors: their tidal deformation. Neutron stars, much like any other extended object with structure, are tidally deformed when under the influence of an external tidal field. In the context of coalescences of neutron stars observed through their gravitational wave emission, this deformation, quantified through a parameter termed the \emph{tidal deformability}, can be measured. We discuss the role of the tidal deformability in observations of coalescing neutron stars with gravitational waves and how it can be used to probe the internal structure of Nature's most compact matter objects. Perhaps inevitably, a large portion of the discussion will be dictated by GW170817, the most informative confirmed detection of a binary neutron star coalescence with gravitational waves as of the time of writing.

中文翻译：

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中子星潮汐变形能力和状态方程约束

尽管中子星有着悠久的历史和天体物理学的重要性，但中子星的一些关键特性仍然不确定。在它们内部遇到的极端条件，包括在极端密度和同位旋不对称下组成不确定的物质，独特地决定了广义相对论中恒星的宏观特性。长期以来，对这些宏观特性（例如中子星的质量和半径）的天体物理学限制一直被用来理解形成它们的物质的微观特性。在这篇文章中，我们讨论了中子星的另一个天体物理学可观测的宏观特性，可用于研究它们的内部：它们的潮汐变形。中子星，就像任何其他具有结构的延伸物体一样，在外部潮汐场的影响下会发生潮汐变形。在通过引力波发射观察到的中子星合并的背景下，可以测量这种变形，通过称为\emph {潮汐变形性}的参数进行量化。我们讨论了潮汐变形性在观测具有引力波的聚结中子星中的作用，以及如何用它来探测自然界最致密物质物体的内部结构。或许不可避免地，讨论的很大一部分将由 GW170817 主导，这是截至撰写本文时对双中子星与引力波合并的最有用的确认检测。我们讨论了潮汐变形性在观测具有引力波的聚结中子星中的作用，以及如何用它来探测自然界最致密物质物体的内部结构。或许不可避免地，讨论的很大一部分将由 GW170817 主导，这是截至撰写本文时对双中子星与引力波合并的最有用的确认检测。我们讨论了潮汐变形性在观测具有引力波的聚结中子星中的作用，以及如何用它来探测自然界最致密物质物体的内部结构。或许不可避免地，讨论的很大一部分将由 GW170817 主导，这是截至撰写本文时对双中子星与引力波合并的最有用的确认检测。