发表机构
Université PSL, Sorbonne Université, Université de Lille; Università degli Studi di Firenze; Université de Strasbourg; Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université（巴黎文理研究大学、索邦大学、里尔大学; 佛罗伦萨大学; 斯特拉斯堡大学; 巴黎天文台、巴黎文理研究大学、索邦大学、巴黎西岱大学、塞吉-蓬图瓦兹大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究基于盖亚数据的非轴对称银河系模型，推导六个银河潮汐参数，发现其沿太阳系轨道变化显著，会影响奥尔特云结构、长周期彗星流量及特定太阳系外系统。
AI 中文摘要
背景：银河潮汐是作用于沉浸在银河系引力势中的延展系统的外部差力，在奥尔特云彗星的动力学中发挥关键作用。目标：我们旨在确定盖亚任务揭示的银河系非轴对称引力势产生的银河潮汐强度，以及该强度如何沿太阳系的银道面轨道演化。方法：我们推导了银河潮汐参数的表达式，这些表达式不依赖于银河系中恒星的任何简化轨道或银河系引力势的任何特定对称性；得到了量化潮汐影响的六个参数$G_1$至$G_6$。使用最新的、扩展至三维的银河系引力势模型，我们采用统计方法研究了这些参数沿太阳轨道的时间演化。结果：即使是本次研究中具有适度径向和垂直偏移的银道面轨道，主导银河参数$G_3$沿太阳轨道的变化也达到一个数量级；$G_1$和$G_2$沿太阳轨道分别达到$G_3$的约二分之一和四分之一，而参数$G_4$至$G_6$达到$G_3$的十分之一。结论：与通常假设的情况相反，所有银河潮汐参数沿太阳系的银道面轨道变化显著。可预期两个结果：其一，$G_3$直接影响可观测长周期彗星的流量和化石塞德娜区的范围；其二，$G_1$、$G_2$以及较小程度上的$G_4$至$G_6$会破坏动力学的可积性，可能影响奥尔特云的长期结构。此外，新参数$G_4$至$G_6$虽对太阳系而言数值较小，但可能对银河系中具有大垂直偏移的太阳系外系统产生强烈影响。
英文摘要
Context. Galactic tides are external differential forces acting on extended systems immersed in the Galactic potential. They play a key role in the dynamics of comets in the Oort cloud. Aims. We aim to establish the strength of Galactic tides from the non-axisymmetric potential of the Milky Way revealed by the Gaia mission, and how this strength evolves along the Galactic trajectory of the Solar System. Methods. We derived expressions for Galactic tide parameters independently of any simplified trajectory for a star in the Galaxy or any specific symmetry of the Galactic potential. We obtained six parameters, $G_1$ to $G_6$, that quantify the influence of tides. Using the most up-to-date Galactic potential model, extended here to three dimensions, we studied the time evolution of these parameters along the Sun's trajectory using a statistical approach. Results. Even for Galactic trajectories featuring modest radial and vertical excursions, as investigated here, the dominant Galactic parameter, $G_3$, is found to vary by an order of magnitude along the solar trajectory. $G_1$ and $G_2$ reach up to about one half and one quarter, respectively, of $G_3$ along the solar trajectory, whilst parameters $G_4$ to $G_6$ reach up to one tenth of $G_3$. Conclusions. Contrary to what is often assumed, all Galactic tide parameters vary widely along the Galactic trajectory of the Solar System. Two consequences can be expected: First, $G_3$ directly affects the flux of observable long-period comets and the extent of the fossilised Sednoids region; second, $G_1$ and $G_2$, and to a lesser extent, $G_4$ to $G_6$, break the integrability of the dynamics, potentially affecting the long-term structure of the Oort cloud. Additionally, the new parameters $G_4$ to $G_6$, while small for the Solar System, may strongly impact extrasolar systems with a large out-of-the-plane excursion in the Galaxy.
CommentsPublished in Astronomy and Astrophysics
Journal refA&A, 712, A162 (2026)
DOI：10.1051/0004-6361/202660056
