In the context of the massive secondary object recently observed in the compact-star merger GW190814, we investigate the possibility of producing massive neutron stars from a few different equation of state models that contain exotic degrees of freedom, such as hyperons and quarks. Our work shows that state-of-the-art relativistic mean-field models can generate massive stars reaching $\gtrsim 2.05{\mathrm{M}}_{\mathrm{Sun}}$, while being in good agreement with gravitational-wave events and x-ray pulsar observations, when quark vector interactions and nonstandard self-vector interactions are introduced. In particular, we present a new version of the Chiral Mean Field (CMF) model in which a different quark-deconfinement potential allows for stable stars with a pure quark core. When rapid rotation is considered, our models generate stellar masses that approach, and in some cases surpass $2.5{\mathrm{M}}_{\mathrm{Sun}}$. We find that in such cases fast rotation does not necessarily suppress exotic degrees of freedom due to changes in stellar central density, but require a larger amount of baryons than what is allowed in the nonrotating stars. This is not the case for pure quark stars, which can easily reach $2.5{\mathrm{M}}_{\mathrm{Sun}}$ and still possess approximately the same amount of baryons as stable nonrotating stars. We also briefly discuss possible origins for fast rotating stars with a large amount of baryons and their stability, showing how the event GW190814 can be associated with a star containing quarks as one of its progenitors.

中文翻译：

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GW190814是巨大的快速旋转的中子星，具有奇特的自由度

在最近在紧凑型恒星合并GW190814中观察到的大量次要物体的背景下，我们研究了通过几种不同的状态模型（包括超子和夸克）从几个不同的状态模型产生大量中子星的可能性，这些状态模型包含外来自由度。我们的工作表明，最先进的相对论平均场模型可以产生大量恒星到达$\gtrsim 2.05{\mathrm{中号}}_{\mathrm{太阳}}$，在引入夸克矢量相互作用和非标准自矢量相互作用的同时，与重力波事件和X射线脉冲星观测非常吻合。特别是，我们提出了一种新版本的手性平均场（CMF）模型，在该模型中，不同的夸克脱限电位允许具有纯夸克核的稳定恒星。当考虑快速旋转时，我们的模型会产生接近的恒星质量，在某些情况下会超过$2.5{\mathrm{中号}}_{\mathrm{太阳}}$。我们发现，在这种情况下，由于恒星中心密度的变化，快速旋转并不一定会抑制奇异的自由度，但与非旋转恒星所允许的相比，需要更多的重子。纯夸克星不是这种情况，可以很容易地达到$2.5{\mathrm{中号}}_{\mathrm{太阳}}$并且仍然拥有与稳定的不旋转恒星大致相同数量的重子。我们还简要讨论了具有大量重子的快速旋转恒星的可能起源及其稳定性，显示了GW190814事件如何与包含夸克的恒星作为其先祖之一相关联。