过去，由于缺乏含有矿物学诊断吸收带的高质量近红外光谱数据（0.7-2.5微米），限制近地小行星的表面组成一直很困难。在这里，我们提出了可见光（0.43-0.95微米）和近红外（0.7-2.5微米）光谱的九个近地小行星和五个火星穿越小行星（MC）。所研究的非经济实体是：4055 Magellan，19764（2000 NF 5），89830（2002 CE），138404（2000 HA 24），143381（2003 BC 21），159609（2002 AQ 3），164121（2003 YT 1），241662（2000 KO 44）和2007 ML 13。它们是：1656 Suomi、2577 Litva、5407（1992 AX）、22449 Ottijeff和47035（1998 WS）。这些观测是由智利拉西拉的NTT、西班牙卡拉尔阿尔托的2.2米望远镜和夏威夷莫纳克亚山的IRTF进行的。小行星的分类学分类（Bus系统）表明，所有观测到的MC小行星都属于S-复合体，包括S、Sr和Sl类。其中7个近地小行星属于S复合体，包括S、Sa、Sk和Sl类，2个近地小行星被划为V型。NEA 164121（2003 YT 1）是根据其近红外光谱被分类为V型的，因为这颗小行星没有可见光谱。对其中六颗小行星（已获得或以前可获得近红外光谱的小行星）进行了矿物学分析。我们发现三颗小行星（241662（2000 KO 44）、19764（2000 NF 5）、138404（2000 HA 24））的镁铁质硅酸盐成分与普通的陨石一致，而另外三颗小行星（4055 Magellan、164121（2003 YT 1）、5407（1992 AX））是以辉石为主的玄武质无球粒陨石组合。在5407（1992 AX）的情况下，我们发现它的玄武岩表面成分与其S型分类相反。
英文摘要：
In the past, constraining the surface composition of near-Earth asteroids (NEAs) has been difficult due to the lack of high quality near-IR spectral data (0.7-2.5 microns) that contain mineralogically diagnostic absorption bands. Here we present visible (0.43-0.95 microns) and near-infrared (0.7-2.5 microns) spectra of nine NEAs and five Mars-crossing asteroids (MCs). The studied NEAs are: 4055 Magellan, 19764 (2000 NF5), 89830 (2002 CE), 138404 (2000 HA24), 143381 (2003 BC21), 159609 (2002 AQ3), 164121 (2003 YT1), 241662 (2000 KO44) and 2007 ML13. The studied MCs are: 1656 Suomi, 2577 Litva, 5407 (1992 AX), 22449 Ottijeff and 47035 (1998 WS). The observations were conducted with the NTT at La Silla, Chile, the 2.2 m telescope at Calar Alto, Spain, and the IRTF on Mauna Kea, Hawai'i. The taxonomic classification (Bus system) of asteroids showed that all observed MC asteroids belong to the S-complex, including the S, Sr and Sl classes. Seven of the NEAs belong to the S-complex, including the S, Sa, Sk and Sl classes, and two NEAs were classified as V-types. The classification of the NEA 164121 (2003 YT1) as a V-type was made on the basis of its near-infrared spectrum since no visible spectrum is available for this asteroid. A mineralogical analysis was performed on six of the asteroids (those for which near-IR spectra were obtained or previously available). We found that three asteroids (241662 (2000 KO44), 19764 (2000 NF5), 138404 (2000 HA24)) have mafic silicate compositions consistent with ordinary chondrites, while three others (4055 Magellan, 164121 (2003 YT1), 5407 (1992 AX)) are pyroxene-dominated basaltic achondrite assemblages. In the case of 5407 (1992 AX) we found that its basaltic surface composition contrasts its taxonomic classification as a S-type.
We present the results of the first-ever visible spectroscopic survey fully dedicated to the small (absolute magnitude H>20) near-Earth asteroid (NEA) population. Observations have been performed at the New Technology Telescope (NTT) of the European Southern Observatory (ESO), during a 30-night Guaranteed Time Observations programme, in the framework of the European Commission financed NEOShield-2 project. The visible spectra of 147 objects have been obtained and taxonomically classified. They show a peculiar taxonomic distribution, with respect to larger NEAs. In particular, olivine-rich A-ty…
We present here the c-o colors for identified Flora, Vesta, Nysa-Polana, Themis, and Koronis family members within the historic data set (2015-2018) of the Asteroid Terrestrial-impact Last Alert System (ATLAS). The Themis and Koronis families are known to be relatively pure C- and S-type Bus-DeMeo taxonomic families, respectively, and the extracted color data from the ATLAS broadband c- and o-filters of these two families is used to demonstrate that the ATLAS c-o color is a sufficient parameter to distinguish between the C- and S-type taxonomies. The Vesta and Nysa-Polana families are known to…
We aim to provide a taxonomic classification for asteroids observed by VISTA-VHS survey. We derive a method for assigning a compositional type to an object based on its (Y-J), (J-Ks), and (H-Ks) colors. We present a taxonomic classification for 18\,265 asteroids from the MOVIS catalog, using a probabilistic method and the k-nearest neighbors algorithm. Because our taxonomy is based only on NIR colors, several classes from Bus-DeMeo were clustered into groups and a slightly different notation was used (i.e. the superscript indicates that the classification was obtained based on the NIR colors a…
We present here multi-band photometry for over 2000 Main-belt asteroids. For each target we report the probabilistic taxonomy using the measured V-R and V-I colors in combination with a machine-learning generated decision surface in color-color space. Through this method we classify >85% of our targets as one the four main Bus-DeMeo complexes: S-, C-, X-, or D-type. Roughly one third of our targets have a known associated dynamic family with 69 families represented in our data. Within uncertainty our results show no discernible difference in taxonomic distribution between family members and no…
The taxonomic distribution of asteroids from multi-filter all-sky photometric surveys
几十年来，人们一直在研究小行星在主带的分布，以了解其组成分布，以及这告诉我们太阳系的形成和演化。现在，全天空调查提供的数据数量级超过有针对性的调查。我们提出了一种方法来纠正偏置的小行星种群在斯隆数字巡天（SDSS）中观察到的大小，距离，和duplex。我们对这个数据集进行分类，与总线和总线DeMeo系统一致，并给出了由此产生的分类分布。该数据集包括小至5公里的小行星，直径比以前的作品小三倍。由于我们的样本中的尺寸范围很广，我们按数量，表面积，体积和质量呈现分布，而以前的工作完全是按数量。虽然数量分布是一个有用的数量，并且已经使用了几十年，但这些额外的数量为总物质的分布提供了新的见解。我们在主带内部发现了D型的证据，根据行星迁移过程中天体从外太阳系注入内太阳系的动力学模型（Levison et al. 2009），它们是意想不到的。我们没有发现S型或其他意想不到的类特洛伊人和希尔达之间的证据，虽然偏向于这样的检测。最后，我们首次估计了内太阳系中各类物质的总量。主带最大的质量级依次为C、B、P、V和S。除了谷神星、智神星、灶神星和仙女座这四颗质量最大的小行星外，原始物质（C型和P型）占了主带和特洛伊小行星质量的一半以上，其余大部分质量都是S型。所有其他类都是火星和木星之间物质的次要贡献者。
The Mission Accessible Near-Earth Object Survey (MANOS) aims to observe and characterize small (mean absolute magnitude H ~ 25 mag) Near-Earth Objects (NEOs) that are accessible by spacecraft (mean $Δv$ ~ 5.7 km/s) and that make close approaches with the Earth (mean Minimum Orbital Intersection Distance MOID ~ 0.03 AU). We present here the first results of the MANOS visible spectroscopic survey. The spectra were obtained from August 2013 to March 2018 at Lowell Observatory's Discovery Channel 4.3 meter telescope, and both Gemini North and South facilities. In total, 210 NEOs have been observed…
The inner asteroid belt between 2.1 and 2.5 au is of particular dynamical significance because it is the dominant source of both chondritic meteorites and near-Earth asteroids. This inner belt is bounded by an eccentricity-type secular resonance and by the 1:3 mean motion resonance with Jupiter. Unless asteroid perihelia are low enough to allow scattering by Mars, escape requires transport to one of the bounding resonances. In addition Yarkovsky forces are generally ineffective in changing either the eccentricity and/or inclination for asteroids with diameter $\gtrsim$30 km. Thus, large astero…
Asteroid phase curves are used to derive fundamental physical properties through the determination of the absolute magnitude H. The upcoming visible Legacy Survey of Space and Time (LSST) and mid-infrared Near-Earth Object Surveillance Mission (NEOSM) surveys rely on these absolute magnitudes to derive the colours and albedos of millions of asteroids. Furthermore, the shape of the phase curves reflects their surface compositions, allowing for conclusions on their taxonomy. We derive asteroid phase curves from dual-band photometry acquired by the Asteroid Terrestrial-impact Last Alert System te…
Context. A region at the inner edge of the main asteroid belt is populated by the Hungaria asteroids. Among these objects, the Hungaria family is formed as the result of a catastrophic disruption of (434) Hungaria asteroid hundred million years ago. Due to the Yarkovsky effect, the fragments depending on their direction of rotation are slowly drifting inward or outward from the actual place of collision. Due to this slow drift these bodies could approach the locations of the various mean-motion resonances (MMRs) of outer type with Mars. Aims. We aim to study the actual dynamical structure of H…
The taxonomic classification of asteroids has been mostly based on spectroscopic observations with wavelengths spanning from the VIS to the NIR. VIS-NIR spectra of $\sim$2500 asteroids have been obtained since the 1970s; the SDSS MOC 4 was released with $\sim$4 $\times$ 10$^{5}$ measurements of asteroid positions and colors in the early 2000s. A number of works then devised methods to classify these data within the framework of existing taxonomic systems. Some of these works, however, used 2D parameter space that displayed a continuous distribution of clouds of data points resulting in boundar…
Context. Small binary asteroid systems and pairs are thought to form through fission induced by spin up via the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect. This process is expected to depend on their structural strength, hence composition. Aims. We aim to determine how taxonomic classes, used as a proxy for composition, distribute amongst binary asteroids and asteroid pairs compared to the general population. Methods. We compare the distribution of taxonomic classes of binary systems and pairs with that of a reference sample of asteroids. We build this sample by selecting asteroids to…
The region occupied by the Hungaria asteroids has a high dynamical complexity. In this paper, we analyse the main dynamic structures and their influence on the known asteroids through the construction of maps of initial conditions. We evolve a set of test particles placed on a perfectly rectangular grid of initial conditions during 3 Myr under the gravitational influence of the Sun and eight planets, from Mercury to Neptune. Moreover, we use the method MEGNO in order to obtain a complete dynamical portrait of the region. A comparison of our maps with the distribution of real objects allows us …
Given rapid photodissociation and photodegradation, the recently discovered organics in the Martian subsurface and atmosphere were probably delivered in geologically recent times. Possible parent bodies are C-type asteroids, comets, and interplanetary dust particles (IDPs). The dust infall rate was estimated, using different methods, to be between $0.71$ and $2.96 \times 10^6$ kg/yr (Nesvorny et al., 2011, Borin et al., 2017, Crismani et al., 2017); assuming a carbon content of 10% (Flynn, 1996), this implies an IDP carbon flux of $0.07 - 0.3 \times 10^6$ kg/yr. We calculate for the first time…
The population of near-Earth asteroids (NEAs) shows a large variety of objects in terms of physical and dynamical properties. They are subject to planetary encounters and to strong solar wind and radiation effects. Their study is also motivated by practical reasons regarding space exploration and long-term probability of impact with the Earth. We aim to spectrally characterize a significant sample of NEAs with sizes in the range of $\sim$0.25 - 5.5 km (categorized as large), and search for connections between their spectral types and the orbital parameters. Optical spectra of NEAs were obtaine…
We investigate the mineralogy of L5 Martian Trojan asteroids via reflectance spectroscopy, in particular (101429) 1998 $\mbox{VF}_{31}$, the only L5 Trojan that does not belong to the Eureka family (Christou, 2013). We find that this asteroid most likely belongs to the Bus-Demeo S-complex, in agreement with Rivkin et al. (2007) and obtain good spectral matches with Sq- or S-type asteroids, the lunar surface and of Martian and lunar meteorites. Mixture fitting to spectral endmembers suggests a surface abundance of Mg-rich orthopyroxene and iron metal or, alternatively, a mixture of plagioclase …
Taxonomic analysis of asteroids with artificial neural networks
Yunnan Observatories, CAS（中国科学院云南天文台）；University of Chinese Academy of Sciences（中国科学院大学）；Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences（中国科学院天体结构与演化重点实验室）；University of Helsinki（赫尔辛基大学）；Deep Space Exploration Laboratory（深空探测实验室）
Gaia DR3 supervised classification of asteroid reflectance spectra
Université Côte d’Azur, CNRS-Lagrange, Observatoire de la Côte d’Azur（蔚蓝海岸大学，CNRS-拉格朗日实验室，蔚蓝海岸天文台）；University of Leicester, School of Physics and Astronomy（莱斯特大学，物理与天文学学院）；University of Leicester, School of Natural Sciences（莱斯特大学，自然科学学院）
The impact flux over the last 3 Ga in the inner Solar System is commonly assumed to be constant through time. However, asteroid break-up events in the main belt may have been responsible for cratering spikes over the last ~2 Ga on the Earth-Moon system. We investigate here the possible variations of the size frequency distributions of impactors from the record of small craters of 521 martian impact craters larger than 20 km in diameter. We show that 49 craters (out of the 521) correspond to the complete crater population of this size formed over the last 600 Ma. Our results on Mars show that t…
The two and three body mean motion resonances with Jupiter and Mars (and possible with Earth) may have significant effect on dynamics of very young close asteroids pairs and families. The most known example is influence 9:16 resonance with Mars to some members of Datura family. It is evident, that evolution of this family can be properly reconstructed only when this fact has taken into account. Here we give the list of asteroid pairs in vicinity of mean motion resonance. One of the results of resonance perturbation may be the temporary compensation of the Yarkovsky drift in the semimajor axis.…
Instituto de Astronomía Teórica y Experimental, CONICET-UNC（CONICET-UNC理论与实验天文研究所）；Instituto de Astrofísica de Andalucía, CSIC（西班牙国家研究委员会安达卢西亚天体物理研究所）；Instituto de Física Aplicada a las Ciencias y las Tecnologías, Universidad de Alicante（阿利坎特大学科学与技术应用物理研究所）；Observatório Nacional/MCTIC（国家天文台（巴西科学、技术、创新和通信部））
We are in an era of large catalogs and, thus, statistical analysis tools for large data sets, such as machine learning, play a fundamental role. One example of such a survey is the Sloan Moving Object Catalog (MOC), which lists the astrometric and photometric information of all moving objects captured by the Sloan field of view. One great advantage of this telescope is represented by its set of five filters, allowing for taxonomic analysis of asteroids by studying their colors. However, until now, the color variation produced by the change of phase angle of the object has not been taken into a…
Artificial neural networks (ANN) have been successfully used in the last years to identify patterns in astronomical images. The use of ANN in the field of asteroid dynamics has been, however, so far somewhat limited. In this work we used for the first time ANN for the purpose of automatically identifying the behaviour of asteroid orbits affected by the M1:2 mean-motion resonance with Mars. Our model was able to perform well above 85% levels for identifying images of asteroid resonant arguments in term of standard metrics like accuracy, precision and recall, allowing to identify the orbital typ…
We explore the hypothesis that the population of Martian Trojans is the result of a balance between the production of new asteroids ("YORPlets") through the YORP effect and their eventual escape from the Trojan clouds through Yarkovsky-driven orbital evolution. Our principal observables are: (5261) Eureka, its family of 8 asteroids and the family-less Trojans (101429) 1998 VF31 & (121514) 1999 UJ7. We model the population evolution as a birth-death random process and assume it is in a steady state. We then simulate the discovery of Trojans to-date and find that family members of 101429 and 121…
Planetary Chaos and the (In)stability of Hungaria Asteroids
匈牙利小行星群位于主小行星带内部，半长轴在1.8至2天文单位之间，离心率低，倾角为16至35度。最近，有人提出匈牙利小行星的数量正在长期下降，这可能与晚期重轰炸（LHB）撞击物有关（Bottke等人，2012年）。虽然Bottke et al.（2012）和Bottke et al.（2012）重现了呈指数下降的匈牙利人种群，但真正的匈牙利人从未被证实具有相同程度的不稳定性。在这里，我们发现，匈牙利的稳定性是强烈依赖于火星的偏心率，这是混乱和不可预测的陀螺时间尺度上的演变。我们发现，火星的高偏心率主要通过与火星的近距离接触而影响匈牙利人，而不是行星的长期模式。然而，匈牙利目前的最小近日点（在百万年时间尺度上）并不能诊断它们的长期稳定性，这是由于一些长期和平均运动共振影响匈牙利地区（Milani等人，2010年）。我们的结论是，行星的混乱使得它不可能确定观察到的匈牙利的有效寿命。此外，火星离心率的长期变化可能导致匈牙利的损失随着时间的推移而变化。我们推测，一些最稳定的匈牙利可能已经被放置在他们目前的轨道时，火星的偏心率明显高于今天。
The classification of the minor bodies of the Solar System based on observables has been continuously developed and iterated over the past 40 years. While prior iterations followed either the availability of large observational campaigns or new instrumental capabilities opening new observational dimensions, we see the opportunity to improve primarily upon the established methodology. We developed an iteration of the asteroid taxonomy which allows the classification of partial and complete observations (i.e. visible, near-infrared, and visible-near-infrared spectrometry) and which reintroduces …
Primitive asteroids in the main belt, Cybele, and Hilda populations from Gaia DR3
LIRA, Université Paris Cité, Observatoire de Paris, Université PSL, Sorbonne Université, CY Cergy Paris Université, CNRS（拉伊特研究所，巴黎西岱大学，巴黎天文台，巴黎文理研究大学，索邦大学，塞吉-巴黎大学，法国国家科学研究中心）；Institut Universitaire de France (IUF)（法兰西学院）；Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency（宇宙科学研究所，日本宇宙航空研究开发机构）
Asteroids can be classified into several groups based on their spectral reflectance. Among these groups, the one belonging to the L-class in the taxonomic classification based on visible and near-infrared spectra exhibit several peculiar properties. First, their near-infrared spectrum is characterized by a strong absorption band interpreted as the diagnostic of a high content of the FeO bearing spinel mineral. This mineral is one of the main constituents of Calcium-Aluminum-rich Inclusions (CAI) the oldest mineral compounds found in the solar system. In polarimetry, they possess an uncommonly …
