近距离系外行星是奇异夸克物质天体的候选者
Close-in Exoplanets as Candidates of Strange Quark Matter Objects
摘要：
由于强子的真正基态可能是奇异夸克物质（SQM），因此强子可能实际上是奇异星而不是中子星。根据这个SQM假说，奇怪的行星也可以稳定存在。正常物质行星的密度很难超过30 g cm $^{-3}$。因此，当它的轨道半径小于$\sim 5.6\times10^{10} \rm \, cm $，或当轨道周期（$P_{\rm orb}$）小于$ \sim \rm 6100\, s $时，它们将被潮汐破坏。相反，一颗陌生的行星即使离宿主非常近，也可以安全地生存下来，因为它的密度很高。该功能可以帮助我们识别SQM对象。在这项研究中，我们试图寻找SQM对象中的近距离系外行星绕恒星。令人鼓舞的是，我们发现四颗脉冲星行星（XTE J1807-294 b，XTE J1751-305 b，PSR 0636 b，PSR J1807- 2459 A b）完全符合$P_{\rm orb} < \rm 6100\, s $的标准，因此是SQM行星的良好候选者。另外两颗行星（PSR J1719+14 b和PSR J2051-0827 b）的轨道周期仅略高于标准。他们可以被视为潜在的候选人。此外，我们还发现了5颗白矮星（GP Com b，V396 Hya b，J1433 b，WD 0137-349 b和SDSS J1411+2009 b）的周期小于0.1天。我们认为它们也可能是SQM行星。进一步发现，这些近距离行星系统中至少有三个系统的持续引力波发射是LISA可以探测到的。更值得注意的是，先进的LIGO和爱因斯坦望远镜能够探测到此类SQM行星系统合并事件产生的引力波爆发，这将为SQM假说提供独特的检验。
英文摘要：
Since the true ground state of the hadrons may be strange quark matter (SQM), pulsars may actually be strange stars rather than neutron stars. According to this SQM hypothesis, strange planets can also stably exist. The density of normal matter planets can hardly be higher than 30 g cm$^{-3}$. As a result, they will be tidally disrupted when its orbital radius is less than $\sim 5.6\times10^{10} \rm \, cm $, or when the orbital period ($P_{\rm orb}$) is less than $ \sim \rm 6100\, s $. On the contrary, a strange planet can safely survive even when it is very close to the host, due to its high density. The feature can help us identify SQM objects. In this study, we have tried to search for SQM objects among close-in exoplanets orbiting around pulsars. Encouragingly, it is found that four pulsar planets (XTE J1807-294 b, XTE J1751-305 b, PSR 0636 b, PSR J1807-2459A b) completely meet the criteria of $P_{\rm orb} < \rm 6100\, s $, and are thus good candidates for SQM planets. The orbital periods of two other planets (PSR J1719+14 b and PSR J2051-0827 b) are only slightly higher than the criteria. They could be regarded as potential candidates. Additionally, we find that the periods of five white dwarf planets (GP Com b, V396 Hya b, J1433 b, WD 0137-349 b, and SDSS J1411+2009 b) are less than 0.1 days. We argue that they might also be SQM planets. It is further found that the persistent gravitational wave emissions from at least three of these close-in planetary systems are detectable to LISA. More encouragingly, the advanced LIGO and Einstein Telescope are able to detect the gravitational wave bursts produced by the merger events of such SQM planetary systems, which will provide a unique test for the SQM hypothesis.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
