论文标题
具有大夸克芯的中子星星
Neutron stars with large quark cores
论文作者
论文摘要
我们使用状态的混合方程来描述$β-$平衡中的电荷中性中子恒星物质，其中实现了一阶相变到夸克物质。望勒围绕饱和密度$ n_0 $的泰勒膨胀以与模型无关的方式描述了辐射物质，而三种效果NJL模型则用于夸克物质。探索目前关于核物质经验参数和NJL模型参数空间的不确定性，我们构建了两个热力学一致和因果杂种EOSS的数据集，与天体物理观察兼容。我们得出的结论是，为了维持相当大的夸克核心大小，从强子到夸克物质的相过渡的强度不能强大，能量密度差距低于$ 200 $ MEV/fm $^3 $，并且必须以巴里昂的密度不超过饱和密度的四倍。需要一个非零但不太强的夸克矢量 - 等级术语和弱向量等级夸克项。在中子恒星内，最大质量$ \ 2.2 m_ \ odot $的大夸克芯在中子星体内有可能几乎一半的恒星质量。为了获得相当数量的混合EOS，可以预测具有质量$ \ sim 1.4 m_ \ odot $的中子星中已经已经存在的夸克物质，我们要求夸克的发作在$ 1.3N_0 $和$ 2.5N_0 $的范围内。如果能量密度间隙和过渡时压力低于100 meV/fm $^3 $，则具有大夸克芯的中子星，相当于总恒星质量的四分之一以上。但是，在这些约束下，最大中子星质量仅限于$ \ Lessim 2.06 m _ {\ odot} $。在半径上没有发现夸克物质的强签名和低于$ 1.8 \，m_ \ odot $的中子星质量的潮汐变形性。
We describe charge-neutral neutron star matter in $β-$equilibrium using hybrid equations of state, where a first-order phase transition from hadronic to quark matter is realized. The hadronic matter is described in a model-independent way by a Taylor expansion around saturation density $n_0$, while the three-flavor NJL model is used for the quark matter. Exploring the present uncertainty on the empirical parameters of nuclear matter and the parameter space of the NJL model, we construct two datasets of thermodynamically consistent and causal hybrid EoSs, compatible with astrophysical observations. We conclude that, to sustain a considerable quark core size, the intensity of the phase transition from hadron to quark matter cannot be strong, having a energy density gap below $200$ MeV/fm$^3$, and must occur at baryon densities not above four times the saturation density. A non zero but not too strong quark vector-isoscalar term and a weak vector isovector quark term are required. Large quark cores carrying almost half of the star mass are possible inside neutron stars with a maximum mass $\approx 2.2 M_\odot$. To get a considerable number of hybrid EoS predicting quark matter already inside neutron stars with a mass $\sim 1.4 M_\odot$, we require that the onset of quarks occurs in the range $1.3n_0$ and $2.5n_0$. Neutron stars with large quark cores corresponding to more than one fourth of the total star mass, are possible if the energy density gap and the pressure at transition are below 100 MeV/fm$^3$. However, under these constraints, the maximum neutron star mass is limited to $ \lesssim 2.06 M_{\odot}$. No strong signatures from quark matter were found on the radius and the tidal deformability for neutron star masses below $1.8\, M_\odot$.
