Tidal Deformations of Hybrid Stars with Sharp Phase Transitions and Elastic Crusts
Tidal Deformations of Hybrid Stars with Sharp Phase Transitions and Elastic Crusts
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DOI：
10.3847/1538-4357/ab8aca
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发表时间：
2020-03
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影响因子：
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通讯作者：
J. P. Pereira;M. Bejger;N. Andersson;F. Gittins
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作者：
J. P. Pereira;M. Bejger;N. Andersson;F. Gittins
引力波天文学有望提供对中子星性质的独立约束，例如它们的状态方程。这是可能的测量的二进制组件的潮汐变形，改变点粒子的引力波形的中子星双星。在这里，我们提供了第一次研究的潮汐变形的影响，由于弹性/固体的地壳（强子相）在混合中子星星，以及夸克-强子相密度跳跃对潮汐变形的影响。我们采用非径向扰动与零频率的框架和研究强子相位呈现弹性方面扰动时（剪切模量约1%的压力）。我们发现，在一个混合星星与一个完美流体夸克相和强子相呈现弹性部分的相对潮汐形变变化是从来没有大于约2%-4%（相对于一个完美流体对应）。当混合星星的弹性区域大于星星半径的60%时，这些最大的变化就会发生，这可能发生在它的夸克相很小而密度跳跃足够大的时候，甚至当混合星星有弹性混合相的时候。在其他情况下，弹性地壳引起的潮汐变形变化可以忽略不计（），因此，即使使用第三代探测器也不太可能测量到。因此，只有当混合星星的弹性强子区域的大小超过其半径的一半时，弹性效应才能对潮汐形变产生显著的影响。
Gravitational wave astronomy is expected to provide independent constraints on neutron-star properties, such as their equation of state. This is possible with the measurements of binary components’ tidal deformability, which alter the point-particle gravitational waveforms of neutron-star binaries. Here, we provide a first study of the tidal deformability effects due to the elasticity/solidity of the crust (hadronic phase) in a hybrid neutron star, as well as the influence of a quark-hadronic phase density jump on tidal deformations. We employ the framework of non-radial perturbations with zero frequency and study hadronic phases presenting elastic aspects when perturbed (with the shear modulus approximately 1% of the pressure). We find that the relative tidal deformation change in a hybrid star with a perfect-fluid quark phase and a hadronic phase presenting an elastic part is never larger than about 2%–4% (with respect to a perfect-fluid counterpart). These maximum changes occur when the elastic region of a hybrid star is larger than approximately 60% of the star’s radius, which may happen when its quark phase is small and the density jump is large enough, or even when a hybrid star has an elastic mixed phase. For other cases, tidal deformation changes due to an elastic crust are negligible ( ) and, therefore, unlikely to be measured even with third generation detectors. Thus, only when the size of the elastic hadronic region of a hybrid star is over half of its radius, could the effects of elasticity have a noticeable impact on tidal deformations.