论文标题
结晶的白矮星的振荡和潮汐变形
Oscillations and tidal deformations of crystallized white dwarfs
论文作者
论文摘要
长期以来，五十多年前，盖亚太空望远镜最近获得了白色矮人中存在晶体核心的有力证据。因此，重要的是要研究晶体如何影响白矮人的性质和动力学。在本文中，我们首先研究了基本（F），界面（I）和剪切（S）振荡模式的频率对晶体芯的尺寸的依赖性。我们发现，I和S模式的频率敏感地取决于核心的大小，而我们选择的白色矮人模型最多只能略微影响F模式的频率。接下来，我们考虑结晶的白色矮人的潮汐变形性，发现仅当核心半径大于恒星半径的70％时，结晶的效果才变得显着。当白矮人完全结晶时，潮汐变形性可能会变化一些至10％。我们还表明，对于纯流体白色矮人的质量，惯性矩，潮汐变形性和F模式频率，存在近似状态的不敏感关系。但是，根据恒星质量和组成，当白矮人结晶时，这些关系可能会受到百分之几的影响。这些变化可能会在白色矮人二进制文件的晚期或合并中发出的引力波留下烙印，这可以通过未来的太空传播引力探测器检测到。
Long predicted more than fifty years ago, strong evidence for the existence of crystalline cores inside white dwarfs has recently been obtained by the Gaia space telescope. It is thus important to investigate how a crystalline core may affect the properties and dynamics of white dwarfs. In this paper, we first study the dependence of the frequencies of the fundamental (f), interfacial (i), and shear (s) oscillation modes on the size of the crystalline core. We find that the frequencies of the i- and s-modes depend sensitively on the size of the core, while the frequency of the f-mode is affected only slightly by at most a few percent for our chosen white dwarf models. We next consider the tidal deformability of crystallized white dwarfs and find that the effect of crystallization becomes significant only when the radius of the core is larger than about 70% of the stellar radius. The tidal deformability can change by a few to about 10 percent when a white dwarf becomes fully crystallized. We also show that there exist approximate equation-of-state insensitive relations connecting the mass, moment of inertia, tidal deformability, and f-mode frequency for pure fluid white dwarfs. Depending on the stellar mass and composition, however, these relations can be affected by a few percent when the white dwarf is crystallized. These changes could leave an imprint on the gravitational waves emitted from the late inspiral or merger of white dwarf binaries, which may be detectable by future space-borne gravitational wave detectors.
