小行星2002 VE 68在发现后不久就被确认为金星的类卫星。当时它的数据弧跨度只有24天，现在是2,947天。在这里，我们重新审视这个显着的对象的动态状态的主题，以及期待其动态的过去，并探讨其未来的轨道演变，这是由近距离接触与地月系统和水星。在我们的计算中，我们使用Hermite积分方案，最新的星历，包括八大行星，月球和三个最大的小行星的扰动。我们确认2002 VE 68目前是金星的准卫星，并且在与地球近距离飞行后至少保持了7,000年。在那次相遇之前，该物体可能已经与金星共轨或在经典的非共振近地物体轨道上移动。该物体从L4特洛伊状态漂移到准卫星阶段。我们还确认，在远日点，与地球危险的近距离接触（0.002 AU以下，在希尔球内）是可能的。我们发现2002 VE 68将作为金星的准卫星存在约500年以上，其动力学演化不仅受地球控制，月球的贡献不可忽略，而且还受水星的影响。2002 VE 68与水星、金星和地球呈现共振（或接近共振）行为。我们的计算表明，在未来10，000年内与地球发生实际碰撞的可能性很小，但以8年的周期发生0.04 AU的碰撞。
英文摘要：
Minor planet 2002 VE68 was identified as a quasi-satellite of Venus shortly after its discovery. At that time its data-arc span was only 24 days, now it is 2,947 days. Here we revisit the topic of the dynamical status of this remarkable object as well as look into its dynamical past and explore its future orbital evolution which is driven by close encounters with both the Earth-Moon system and Mercury. In our calculations we use a Hermite integration scheme, the most updated ephemerides and include the perturbations by the eight major planets, the Moon and the three largest asteroids. We confirm that 2002 VE68 currently is a quasi-satellite of Venus and it has remained as such for at least 7,000 yr after a close fly-by with the Earth. Prior to that encounter the object may have already been co-orbital with Venus or moving in a classical, non-resonant Near-Earth Object (NEO) orbit. The object drifted into the quasi-satellite phase from an L4 Trojan state. We also confirm that, at aphelion, dangerously close encounters with the Earth (under 0.002 AU, well inside the Hill sphere) are possible. We find that 2002 VE68 will remain as a quasi-satellite of Venus for about 500 yr more and its dynamical evolution is controlled not only by the Earth, with a non-negligible contribution from the Moon, but by Mercury as well. 2002 VE68 exhibits resonant (or near resonant) behavior with Mercury, Venus and the Earth. Our calculations indicate that an actual collision with the Earth during the next 10,000 yr is highly unlikely but encounters as close as 0.04 AU occur with a periodicity of 8 years.
The dynamically hazardous asteroid 2025 TV$_{10}$. A new co-orbital asteroid of Venus
São Paulo State University (UNESP)（圣保罗州立大学）；Laboratório Interinstitucional de e-Astronomia（跨机构电子天文学实验室）；LIRA, Observatoire de Paris, Université PSL, Sorbonne Université, Université Paris Cité, CY Cergy Paris Université, CNRS（LIRA，巴黎天文台，巴黎文理研究大学，索邦大学，巴黎西岱大学，CY塞尔吉巴黎大学，法国国家科学研究中心）
The composition the atmosphere of Venus results from the integration of many processes entering into play over the entire geological history of the planet. Determining the elemental abundances and isotopic ratios of noble gases (He, Ne, Ar, Kr, Xe) and stable isotopes (H, C, N, O, S) in the Venus atmosphere is a high priority scientific target since it could open a window on the origin and early evolution of the entire planet. This chapter provides an overview of the existing dataset on noble gases and stable isotopes in the Venus atmosphere. The current state of knowledge on the origin and ea…
In the study of planetary habitability and terrestrial atmospheric evolution, the divergence of surface conditions for Venus and Earth remains an area of active research. Among the intrinsic and external influences on the Venusian climate history are orbital changes due to giant planet migration that have both variable incident flux and tidal heating consequences. Here, we present the results of a study that explores the effect of Jupiter's location on the orbital parameters of Venus and subsequent potential water loss scenarios. Our dynamical simulations show that various scenarios of Jovian …
Venus's past climate evolution is uncertain. General circulation model simulations permit a habitable climate as late as ~0.7 Ga, and there is suggestive-albeit inconclusive-evidence for previous liquid water from surface geomorphology and mineralogy. However, it is unclear whether a habitable past can be reconciled with Venus's inferred atmospheric evolution. In particular, the lack of leftover atmospheric oxygen argues against recent water loss. Here, we apply a fully coupled model of Venus's atmospheric-interior-climate evolution from post-accretion magma ocean to present. The model self-co…
Venus' mass and radius are similar to those of Earth. However, dissimilarities in atmospheric properties, geophysical activity and magnetic field generation could hint towards significant differences in the chemical composition and interior evolution of the two planets. Although various explanations for the differences between Venus and Earth have been proposed, the currently available data are insufficient to discriminate among the different solutions. Here we investigate the possible range of Venus structure models. We assume that core segregation happened as a single-stage event. The mantle…
The composition of meteoritic material delivered to the terrestrial planets after the end of core formation as late accretion remains contentious. Because the evolution of Venus' atmospheric composition is likely to be less intricate than the Earth's, we test implications of wet and dry late accretion compositions, using present-day Venus atmosphere measurements. Here we investigate the long-term evolution of Venus using self-consistent numerical models of global thermochemical mantle convection coupled with both an atmospheric evolution model and a late accretion N-body delivery model. Atmosp…
This work reviews the long-term evolution of the atmosphere of Venus, and modulation of its composition by interior-exterior cycling. The formation and evolution of Venus's atmosphere, leading to contemporary surface conditions, remain hotly debated topics, and involve questions that tie into many disciplines. We explore these various inter-related mechanisms which shaped the evolution of the atmosphere, starting with the volatile sources and sinks. Going from the deep interior to the top of the atmosphere, we describe volcanic outgassing, surface atmosphere interactions, and atmosphere escape…
During the late stage of terrestrial planet formation, hit-and-run collisions are about as common as accretionary mergers, for expected velocities and angles of giant impacts. Average hit-and-runs leave two major remnants plus debris: the target and impactor, somewhat modified through erosion, escaping at lower relative velocity. Here we continue our study of the dynamical effects of such collisions. We compare the dynamical fates of intact runners that start from hit-and-runs with proto-Venus at 0.7 AU and proto-Earth at 1.0 AU. We follow the orbital evolutions of the runners, including the o…
On the orbital evolution of 2020 AV2, the first asteroid ever observed to go around the Sun inside the orbit of Venus
太阳系的最内层尚未得到广泛的研究，因为在地球轨道内运动的小天体往往在其恒星轨道周期的大部分时间里处于非常低的太阳伸长，远离搜索近地天体的方案经常观测到的区域。从兹威基瞬变设施进行的调查是第一个能够探测到与地月系统直接引力扰动分离的多个小行星的调查。ZTF的发现包括2019 AQ 3和2019 LF 6，这两颗Atiras是已知小行星中周期最短的。在这里，我们对2020 AV 2的轨道演化进行了评估，这是ZTF发现的Atira，具有类似的短周期，但遵循完全包含在金星轨道内的路径。这一特性使它成为难以捉摸的瓦蒂拉种群的第一个已知成员。真正的Vatiras，那些长期动态稳定的，被认为是受到所谓的冯齐佩尔-利多夫-科扎伊振荡，保护他们免受近距离接触水星和金星。然而，2020 AV 2似乎是前Atira，最近进入Vatira轨道域。它显示出偏心率和倾角值的反耦合振荡，但近日点辐角的值可能会循环。模拟显示，2020年AV 2可能会在未来与金星达到3：2的共振轨道，激活冯齐佩尔-利多夫-科扎伊机制，这反过来又为长期稳定的Vatiras种群的存在打开了可能性。
The discovery and characterization of Earth-sized planets that are in, or near, a tidally-locked state are of crucial importance to understanding terrestrial planet evolution, and for which Venus is a clear analog. Exoplanetary science lies at the threshold of characterizing hundreds of terrestrial planetary atmospheres, thereby providing a statistical sample far greater than the limited inventory of terrestrial planetary atmospheres within the Solar System. However, the model-based approach for characterizing exoplanet atmospheres relies on Solar System data, resulting in our limited inventor…
Modern terrestrial planet formation models are highly successful at consistently generating planets with masses and orbits analogous to those of Earth and Venus. In stark contrast to classic theoretical predictions and inferred demographics of multi-planet systems of rocky exoplanets, the mass (>10) and orbital period (>2) ratios between Venus and Earth and the neighboring Mercury and Mars are not common outcomes in numerically generated systems. While viable solutions to the small-Mars problem are abundant in the literature, Mercury's peculiar origin remains rather mysterious. In this paper, …
Dancing with Venus in the shadow of the Earth: a pair of genetically related near-Earth asteroids trapped in a mean-motion resonance
YORP引起的裂变事件可能形成动态相干的小行星对甚至家族。这一过程的结果在主要小行星带的成员中有详细记载，但在近地小行星群中则没有，因为它们的路径在短时间内非常有效地随机化。平均运动共振（MMR）可以通过使小天体避免与行星近距离接触来稳定它们的轨道。从理论上讲，被困在MMR中的小行星的YORP引发的裂变即使在近地空间也可以保留这一过程的证据。在这里，我们发现两个NEAs，2017 SN 16和2018 RY 7，目前正在遵循轨道演化，由于与金星的3：5 MMR的稳定作用，它们的相对平均经度没有表现出任何长期增加。使这种结构成为可能的机制可能在太阳系和其他地方都起作用。我们的分析表明，2017 SN 16 -2018 RY 7可能起源于两种机制之一：YORP诱导的分裂或二元解离。
Terrestrial exoplanets in habitable zones are ubiquitous. It is, however, unknown which have Earth-like or Venus-like climates. Distinguishing different planet-types is crucial for determining whether a planet could be habitable. We investigate the potential of polarimetry for distinguishing exo-Earths from exo-Venuses. We present computed fluxes and polarisation of starlight that is reflected by exoplanets with atmospheres in evolutionary states from current Earth to current Venus, with cloud compositions ranging from pure water to 0.75 sulfuric acid solution, for wavelengths between 0.3 and …
Coupled atmospHere Interior modeL Intercomparison (CHILI). I. Evolutionary Modelling -- Primordial Magma Oceans of Earth and Venus
Institute of Astronomy, University of Cambridge（剑桥大学天文学研究所）；University of Washington（华盛顿大学）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；Stanford University（斯坦福大学）；National Astronomical Observatory of Japan（日本国立天文台）；Laboratoire de Mathématiques de Versailles（凡尔赛数学实验室）；Université Paris Cité, Institut de physique du globe de Paris, CNRS（巴黎西岱大学，巴黎地球物理学院，法国国家科学研究中心）；University of Central Florida（中佛罗里达大学）；Johns Hopkins University（约翰斯·霍普金斯大学）；SRON Netherlands Research Organisation（荷兰研究组织SRON）；Leiden Observatory, University of Leiden（莱顿大学莱登天文台）；School of Physics, University of Bristol（布里斯托大学物理学院）；Institut für Geologische Wissenschaften, Freie Universität Berlin（柏林自由大学地质科学研究所）
The key goals of the astrobiology community are to identify environments beyond Earth that may be habitable, and to search for signs of life in those environments. A fundamental aspect of understanding the limits of habitable environments and detectable signatures is the study of where such environments can occur. Thus, the need to study the creation, evolution, and frequency of environments hostile to habitability is an integral part of the astrobiology story. The study of these environments provides the opportunity to understand the bifurcation between habitable and uninhabitable conditions …
Here we discuss the current state of knowledge on how atmospheric escape processes can fractionate noble gas isotopes and moderately volatile rock-forming elements that populate primordial atmospheres, magma ocean related environments, and catastrophically outgassed steam atmospheres. Variations of isotopes and volatile elements in different planetary reservoirs keep information about atmospheric escape, composition and even the source of accreting material. We summarize our knowledge on atmospheric isotope ratios and discuss the latest evidence that proto-Venus and Earth captured small H$_2$-…
With the discovery of TRAPPIST-1 and its seven planets within 0.06 au, the correct treatment of tidal interactions is becoming necessary. The eccentricity, rotation, and obliquity of the planets of TRAPPIST-1 are indeed the result of tidal evolution over the lifetime of the system. Tidal interactions can also lead to tidal heating in the interior of the planets, which can then be responsible for volcanism and/or surface deformation. In the majority of studies to estimate the rotation of close-in planets or their tidal heating, the planets are considered as homogeneous bodies and their rheology…
We have studied the geological time evolution of volcanism in Earth and other inner solar system planetary bodies (Mercury, Moon, Mars and Venus) in both geophysical and biophysical perspective. The record of Large Igneous Provinces in Earth and other planetary objects suggest the existence of increasing, decreasing and cessation phases of major volcanic activity over geological time scales. We have extended the existing scale of measuring intensity of volcanic eruptions based on Earth based observations to accommodate intense and extreme volcanic activity. The mass of a rocky planetary object…
The Earth Trojans are co-orbitals librating around the Lagrange points $L_4$ or $L_5$ of the Sun-Earth system. Although many numerical studies suggest that they can maintain their dynamical status and be stable on timescales up to a few tens of thousands of years or even longer, they remain an elusive population. Thus far only one transient member (2010 TK$_7$) has been discovered serendipitously. Here, we present a dynamical study of asteroid 2020 XL$_5$. With our meticulous followup astrometric observations of the object, we confirmed that it is a new Earth Trojan. However, its eccentric orb…
Infrequent visitors of the Kozai kind: the dynamical lives of 2012 FC71, 2014 EK24, 2014 QD364, and 2014 UR
上下文半长轴非常接近主行星的小行星，当它们的节点位于近日点和远日点时，可以避免节点交叉。这种布局保护小行星免受近距离接触，并最终与宿主行星碰撞。目的。在这里，我们研究了最近发现的四颗近地小行星（NEAs）的短期动力学演化-2012 FC 71，2014 EK 24，2014 QD 364和2014 UR-它们遵循非常类似地球的轨道。方法.我们的分析是基于直接N体计算的结果，使用最新的星历表，包括来自八大行星，月球，冥王星-冥卫一系统的重心，和三个最大的小行星的扰动。结果这四个近地小行星的轨道演变不同于任何其他已知近地天体。除了马蹄形、蝌蚪形或准卫星轨道外，它们还在Kozai域内沿着相对于地球的共轨通过轨道运行。我们的计算表明，长期的相互作用诱导的相对论点近日点相对于我们的星球，但也金星，火星和木星的天平动。世俗的混乱也存在。这一流动人口的规模可能很大。结论.虽然其中一些近地小行星可以在数千年内保持轨道稳定，但它们的长期动力学比通常认为的要复杂得多，而且由于多个长期共振的重叠，无法单独在三体问题的框架内进行适当描述。这类天体属于在有利能见度窗口方面最不典型的近地天体，因为它们在时间上相隔几十年甚至几个世纪。
