发表机构
Jülich Supercomputing Center, Forschungszentrum Jülich（于利希超级计算中心，于利希研究中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过数值N体模拟分析45.6亿年间恒星飞掠后TNOs与行星的相互作用，发现该过程能更好拟合观测结果，强化了恒星近距离飞掠太阳系的论点。
AI 中文摘要
海王星外天体（TNOs）与行星一同由扁平的气体尘埃盘形成，如今大多在倾斜、偏心率的轨道上绕太阳运行。对TNOs轨道的一种解释是另一颗恒星的近距离飞掠，质量为$M_p=0.8M_\text{sun}$、近心点距离$q_p=110$天文单位、轨道倾角$i_p=70^\text{o}$的恒星符合观测结果。然而，这类近距离相遇在太阳年轻时仍处于诞生星团中时更为频繁。假设飞掠发生在那时，我们采用数值N体模拟，模拟自太阳形成以来45.6亿年间，TNOs与行星相互作用如何改变其轨道。研究发现，冷柯伊伯带区域损失了约80%的初始天体，热柯伊伯带天体种群损失约40%；约7%至8%的TNOs被注入行星区域，但几乎全部（99%）随后被 ejected；相比之下，遥远的类塞德娜天体（$q>60$天文单位）的轨道参数基本保持不变。令人惊讶的是，这些变化总体上进一步提升了与观测到的TNO种群的拟合度，强化了恒星近距离飞掠太阳系的论点。剩余差异涉及冷天体的位置和类塞德娜天体的倾角分布，我们讨论了可能的原因及解决这些问题的步骤。
英文摘要
The Trans-Neptunian objects (TNOs) formed together with the planets from a flat disc of gas and dust but now orbit the Sun mostly on inclined, eccentric orbits. One explanation for the TNOs' orbits is a close flyby of another star. One with a mass of $M_p =$0.8 Msun at $q_p =$ 110 au and $i_p =$70° fits the observations. However, such close encounters were more frequent when the Sun was young and still part of its birth cluster. Assuming that the flyby happened then, we use numerical $N$-body simulations to model how the TNOs' orbits changed due to interactions with the planets over the 4.56 Gyr since the Sun formed. We find that the cold Kuiper belt region lost about 80% and the hot Kuiper belt population about 40% of its initial population. About 7% --8% of the TNOs were injected into the planet region, but almost all (99%) were ejected afterwards. By contrast, the orbital parameters of distant Sedna-like objects ($q >$60 au) remained basically unchanged. Surprisingly, in sum, these changes improve the fit to the observed TNO population even more, strengthening the argument for a close flyby to the Solar System. The remaining differences concern the location of the cold population and the inclination distribution of the Sedna population. We discuss possible reasons and steps to resolve these issues.
Comments13 pages, 9 Figures, submitted to AAS journals
