标题： 来自恒星四极矩的相互倾斜分布 显示英文标题

标题： The distribution of mutual inclinations arising from the stellar quadrupole moment

摘要： 大量凌日行星系统似乎只拥有一个行星，而不是多个凌日行星。 这种单行星的过剩表明在许多行星系统中存在显著的相互倾斜，但这些不对齐的起源尚不清楚。 此外，最近的观测特征显示，相互倾斜随着靠近恒星而增加。 这些趋势都与恒星早期快速旋转阶段产生的强四极势的动力学影响一致，同时伴随着非零的恒星倾角。 在此，我们模拟了一组行星系统，这些系统受到形成后恒星收缩和自转减慢过程中产生的倾斜、扁平恒星的长期扰动。 我们证明，这种机制可以再现行星之间相互倾斜随靠近恒星而增加的一般趋势，并确定了恒星可以引发动力不稳定的参数空间。 我们认为大约5-10%的低质量开普勒系统可能容易受到这种不稳定机制的影响，这表明大量单次凌日行星可能是内在的单一行星。 我们还报告了不稳定性和恒星倾角减少之间的新联系，并提出了可以在即将到来的TESS观测中进行测试的预测。 显示英文摘要

摘要： A large proportion of transiting planetary systems appear to possess only a single planet as opposed to multiple transiting planets. This excess of singles is indicative of significant mutual inclinations existing within a large number of planetary systems, but the origin of these misalignments is unclear. Moreover, recent observational characterization reveals that mutual inclinations tend to increase with proximity to the host star. These trends are both consistent with the dynamical influence of a strong quadrupolar potential arising from the host star during its early phase of rapid rotation, coupled with a non-zero stellar obliquity. Here, we simulate a population of planetary systems subject to the secular perturbation arising from a tilted, oblate host star as it contracts and spins down subsequent to planet formation. We demonstrate that this mechanism can reproduce the general increase in planet-planet mutual inclinations with proximity to the host star, and delineate a parameter space wherein the host star can drive dynamical instabilities. We suggest that approximately 5-10\% of low-mass Kepler systems are susceptible to this instability mechanism, suggesting that a significant number of single-transiting planets may truly be intrinsically single. We also report a novel connection between instability and stellar obliquity reduction and make predictions that can be tested within upcoming TESS observations.