We numerically simulate the past tidal evolution of the five large moons of Uranus (Miranda, Ariel, Umbriel, Titania, and Oberon). We find that the most recent major mean-motion resonance (MMR) between any two moons, the Ariel-Umbriel 5:3 MMR, had a large effect on the whole system. Our results suggest that this resonance is responsible for the current 4.3$^{\circ}$ inclination of Miranda (instead of previously proposed 3:1 Miranda-Umbriel MMR), and that all five moons had their inclinations excited during this resonance. Miranda experienced significant tidal heating during the Ariel-Umbriel 5:3 MMR due to its eccentricity being excited by Ariel's secular perturbations. This tidal heating draws energy from shrinking of Miranda's orbit, rather than Ariel's outward evolution, and can generate heat flows in excess of 100 mW m$^{-2}$, sufficient to produce young coronae on Miranda. We find that this MMR was followed by a sequence of secular resonances, which reshuffled the moons' eccentricities and inclinations. We also find that the precession of Oberon's spin axis is close to a resonance with the precession of Umbriel's orbital plane, and that this spin-orbit resonance was likely excited during the Ariel-Umbriel 5:3 MMR. After the exit from the MMR, subsequent Ariel-Umbriel secular resonance and Oberon-Umbriel spin-orbit resonance may be able to explain the current low inclinations of Ariel and Umbriel. The age of Miranda's surface features tentatively suggests Uranian tidal $Q=15,000-20,000$, which can be further refined in future work.
The fragility of the Uranian moons during the giant planet instability
Johns Hopkins APL(约翰斯·霍普金斯大学应用物理实验室);Planetary Science Institute(行星科学研究所);University of Oklahoma(俄克拉荷马大学);Rice University(莱斯大学);Southwest Research Institute(西南研究院)
Capture and escape from the 2:1 resonance between Ariel and Umbriel in a fast-migration scenario of the Uranian system
University of Pisa(比萨大学);Anton Pannekoek Institute for Astronomy, University of Amsterdam(阿姆斯特丹大学安东·范·列文虎克天文学研究所);Université PSL, Sorbonne Université, Université de Lille(巴黎文理研究大学、索邦大学、里尔大学)
Comparative orbital evolution of transient Uranian co-orbitals: exploring the role of ephemeral multibody mean motion resonances
天王星有三个已知的共轨道:83982 Crantor(2002 GO 9),2010 EU 65和2011 QF 99。在这里,我们对这些瞬态共轨道的轨道演化进行了比较分析,以更好地了解它们是如何首先被捕获的,以及是什么使它们动态不稳定。我们还在已知的天体中寻找额外的临时天王星共轨候选者。我们的N体模拟表明,2011 QF 99的长期稳定性是由木星和海王星控制的;在成为特洛伊之前,它短暂地进入了与木星的1:7平均运动共振和与海王星的2:1平均运动共振。在这些短暂的两体平均运动共振事件,拱心共转共振也被观察到。对于已知的共轨道,土星是目前主要的不稳定力的来源,但这还不足以将一个次要的天体从与天王星的1:1的轨道中弹射出来。这些物体必须与木星和海王星进入平均运动共振,以便被捕获或成为路过的半人马座。小行星2010 EU 65,可能是来自奥尔特云的访客,由于其相对较低的离心率,可能已经稳定了好几百万年。此外,我们表明,已知对象的轨道特性和发现情况可以用来概述一个实用的策略,通过该策略可以找到更多的天王星的共轨道。
Stability Mapping of the New Uranian Moon S/2025 U1 with Updated Masses for Cordelia, Ophelia, and Cressida
Federal Institute of Education, Science and Technology of Alagoas (IFAL)(阿拉戈阿斯联邦教育、科学和技术学院);Group of Orbital & Rotational Research in Irregular Objects & Observational astroNomy (ORION), Unesp(不规则天体轨道与旋转研究及观测天文小组(ORION),圣保罗州立大学);Group of Orbital Dynamics & Planetology, São Paulo State University (Unesp), School of Engineering and Sciences(圣保罗州立大学(Unesp)工程与科学学院轨道动力学与行星学小组)
The Dynamical History Of 2060 Chiron And Its Proposed Ring System
2013年,令人惊讶地发现了半人马座10199 Chariklo周围的环系统,这导致Ortiz等人重新分析了半人马座2060 Chiron的恒星掩星数据。在这项工作中,我们研究了拟议的凯龙星环系统的动力学历史,通过整合近36,000个半人马座的克隆,在太阳和四个巨行星的影响下,在时间上向后追溯了1亿年。当克隆人在半人马座地区时,所有克隆人和行星之间的近距离接触的严重程度都被记录下来,以及近距离接触之间的平均时间。我们发现严重和极端的近距离接触是非常罕见的,这使得凯龙星环系统自注入半人马座地区以来一直保持完整,我们发现这可能发生在过去的850万年内。我们的模拟产生了一个向后的动力学半衰期为0.7百万年的凯龙。研究发现,由于平均运动共振中的共振粘滞,共振跳跃克隆的半人马寿命平均是随机行走克隆的2倍。此外,我们提出的MEGNO和混沌的寿命地图的13 AU $\le a \le$ 14 AU和电子$\le$ 0.5的区域。我们证实了Chiron的当前平均轨道参数位于a-e相空间的高度混沌区域。
Planet Occurrence Rate Correlated to Stellar Dynamical History: Evidence from Kepler and Gaia
恒星的动力学历史对行星的形成和演化有着重要的影响。为了从观测中探索动力学历史对行星形成和演化的影响,我们假设经历了显著不同动力学历史的恒星往往具有不同的相对速度。利用精确的Gaia-Kepler星表,我们选取了单个主序星,并根据它们的相对速度将它们分为高V、中V和低V三组。在考虑了开普勒观测数据的已知偏差后,采用先验和后验校正方法,使恒星性质对行星出现率的影响最小化,发现高V星的超地球和次海王星出现率(1--4 R $_{\rm \oplus}$,P<100天)比低V星低,而次地球出现率(0.5--1 R $_{ \oplus}$,P<30天)比低V星高。此外,高V恒星有较低的热木星大小的行星的出现率(4- 20 R $_{\oplus}$,P<10天)和略高的热或冷木星大小的行星的出现率(4- 20 R $_{\oplus}$,10<P<400天)。通过对多重数和偏心率的研究,发现高V行星宿主更倾向于多行星系统的比例更高、平均偏心率更低,这与Kepler行星系的偏心率-多重数二分法相一致。所有这些统计结果支持这样的假设,即相对速度大的高V星可能经历较少的引力事件,而低V星可能受到恒星成团的显著影响。
A Multi-Epoch Study of the Radio Continuum Emission of Orion Source I: Constraints on the Disk Evolution of a Massive YSO and the Dynamical History of Orion BN/KL