标题： 致星 hosting 双星的轨道结构 III. 测试三恒星系统中恒星和行星轨道的相互倾角 显示英文标题

标题： Orbital Architectures of Planet-Hosting Binaries III. Testing Mutual Inclinations of Stellar and Planetary Orbits in Triple-Star Systems

摘要： 多恒星系统中的凌星行星，尤其是高阶多重系统，虽然只占已知行星数量的一小部分，但为研究行星形成的环境提供了独特的机会。研究表明，恒星-行星双星系统的恒星轨道与凌星行星轨道对齐的系统数量较多，这可能有助于揭示此类系统的行星形成过程。我们在此探讨这种对齐趋势是否也适用于恒星-行星三合星系统。 我们展示了对一组新型恒星-行星三合星系统的长期天体测量监测，这些系统都包含开普勒任务中发现的凌星行星。通过对我们的凯克自适应光学数据以及一些系统的盖亚天体测量数据进行同质化分析，我们在21个系统中测定了轨道弧线，其中包括12个新确认的三合星系统。我们检查了九个最紧凑系统（<$\lesssim500$au）内的轨道对齐情况，测试了恒星轨道是否与它们的凌星行星的边缘轨道对齐。 我们的三合星样本显示了一种倾向于对齐的趋势，特别是在使用从完整轨道拟合计算出的恒星轨道倾角来评估对齐概率时，但正式来看仍与各向同性轨道一致。当一半的恒星轨道由类似行星-双星系统的适度对齐分布描述，而另一半（非行星-宿主）具有科扎伊型错位分布时，两组模型的测试结果最为匹配。总体而言，我们的结果表明，我们的三恒星行星宿主系统样本并非完全共面系统，至多只有一个对齐平面。 显示英文摘要

摘要： Transiting planets in multiple-star systems, especially high-order multiples, make up a small fraction of the known planet population but provide unique opportunities to study the environments in which planets would have formed. Planet-hosting binaries have been shown to have an abundance of systems in which the stellar orbit aligns with the orbit of the transiting planet, which could give insights into the planet formation process in such systems. We investigate here if this trend of alignment extends to planet-hosting triple-star systems. We present long-term astrometric monitoring of a novel sample of triple-star systems that host Kepler transiting planets. We measured orbit arcs in 21 systems, including 12 newly identified triples, from a homogeneous analysis of our Keck adaptive optics data and, for some systems, Gaia astrometry. We examine the orbital alignment within the nine most compact systems ($\lesssim500$ au), testing if either (or both) of the stellar orbits align with the edge-on orbits of their transiting planets. Our statistical sample of triple systems shows a tendency toward alignment, especially when assessing the alignment probability using stellar orbital inclinations computed from full orbital fits, but is formally consistent with isotropic orbits. Two-population tests where half of the stellar orbits are described by a planet-hosting-binary-like moderately aligned distribution give the best match when the other half (non-planet-hosting) has a Kozai-like misaligned distribution. Overall, our results suggest that our sample of triple-star planet-hosting systems are not fully coplanar systems and have at most one plane of alignment.