Binary asteroids probe thermal-radiation effects on the main-belt asteroids' evolution. We discuss the possibility of detecting binary minor planet systems by the astrometric wobble of the center-of-light around the center-of-mass. This method enables the exploration of the phase-space of binary asteroids, which is difficult to explore using common detection techniques. We describe a forward model that projects the center-of-light position with respect to the center-of-mass, as it is seen by the observer. We study the performance of this method using simulated Gaia-like data. We apply the astrometric method to a subset of the Gaia DR2 Solar System catalog and find no significant evidence of binary asteroids. This is likely because the Gaia DR2 removed astrometric outliers, which in our case may be due to astrophysical signals. Applying this method to binary asteroid (4337) Arecibo, for which Gaia DR3 reported a possible astrometric signal with a period of P = 32.85+/-0.38 hr, reveals a possible 2.2-sigma solution with a period of 16.26 hr (about half the reported period). We find a small, marginally significant, excess of astrometric noise in the known binary asteroid population from Pravec et al. relative to the entire asteroid population in the Gaia DR2 Solar System catalog. We also discuss some caveats like precession and asteroid rotation.
Astrometric follow-up of near-Earth asteroid 2024 YR4 during a Torino scale level 3 alert
European Space Agency（欧洲航天局）；University of Hawaii（夏威夷大学）；New Mexico Tech（新墨西哥理工学院）；Astronomical Institute of the Czech Academy of Sciences（捷克科学院天文研究所）；University of Arizona（亚利桑那大学）
Astrometric and Photometric Investigations of 2009 WZ104 Near Earth Asteroid
2009年11月25日，美国亚利桑那州莱蒙山天文台的68厘米施密特卡特琳娜巡天望远镜发现了WZ 104小行星。新物体的观测结果得到了Schiaparelli天文台（意大利）60厘米反射镜和Alter Saltzberg天文台（奥地利维也纳）35厘米施密特-卡塞格伦望远镜的证实。这颗小行星被认为是潜在的危险近地小行星。最小轨道相交距离为0.0304 a.e.。自2009年底以来，普尔科沃天文台（俄罗斯）的MTM-500 M 50厘米弯月望远镜和ZA-320 M 32厘米镜面天体照相机继续对2009 WZ 104小行星进行观测。这些观测是在近地天体调查方案的框架内进行的。为调查确定了以下任务：获得天体测量和测光（BVRI波段）系列观测，根据观测数据改进小行星轨道，确定其分类类别和绝对星等，调查其旋转动力学，估计其物理参数。这颗小行星属于小行星群中的Aten。
Astrometric positions of moving objects in the Solar System have been measured using a variety of star catalogs in the past. Previous work has shown that systematic errors in star catalogs can affect the accuracy of astrometric observations. That, in turn, can influence the resulting orbit fits for minor planets. In order to quantify these systematic errors, we compare the positions and proper motion of stellar sources in the most utilized star catalogs to the second release of the Gaia star catalog. The accuracy of Gaia astrometry allows us to unambiguously identify local biases and derive a …
We present an updated set of near-Earth asteroids with a Yarkovsky-related semimajor axis drift detected from the orbital fit to the astrometry. We find 87 reliable detections after filtering for the signal-to-noise ratio of the Yarkovsky drift estimate and making sure the estimate is compatible with the physical properties of the analyzed object. Furthermore, we find a list of 24 marginally significant detections, for which future astrometry could result in a Yarkovsky detection. A further outcome of the filtering procedure is a list of detections that we consider spurious because unrealistic…
Outer main belt asteroid (223) Rosa is a possible flyby target of opportunity for ESA's (European Space Agency) JUpiter ICy moons Explorer (JUICE) mission when passing the asteroid belt on the way to Jupiter. The very low albedo and the featureless red spectra indicate a P-type asteroid in the Tholen taxonomy, though the yet known bulk density did not match very well this classification. Aim of this work was to derive new estimates for the mass and for the bulk density for (223) Rosa. The mass of Rosa was derived by analyzing the gravitational deflection of small `test' asteroids which had a c…
Follow the wobble: Statistical methods to detect astrometric binary asteroids in Gaia FPR
Université Côte d’Azur, Observatoire de la Côte d’Azur, CNRS, Laboratoire Lagrange（蔚蓝海岸大学、蔚蓝海岸天文台、法国国家科学研究中心、拉格朗日实验室）；Laboratoire Temps Espace (LTE), Observatoire de Paris, Université PSL, Sorbonne Université（时空实验室（LTE）、巴黎天文台、巴黎文理研究大学、索邦大学）；Polytechnic Institute of Advanced Sciences-IPSA（高级科学理工学院-IPSA）；Lowell Observatory（洛厄尔天文台）；Department of Physics, Aristotle University（亚里士多德大学物理系）
With the inception of gravitational wave astronomy, astrophysical studies using interferometric techniques have begun to probe previously unknown parts of the universe. In this work, we investigate the potential of a new interferometric experiment to study a unique group of gravitationally interacting sources within our solar system: binary asteroids. We present the first study into binary asteroid detection via gravitational signals. We identify the interferometer sensitivity necessary for detecting a population of binary asteroids in the asteroid belt. We find that the space-based gravitatio…
We developed two different point spread function (PSF) analysis techniques for discovering wide separation binary asteroids in wide field surveys. We then applied these techniques to images of main belt asteroids in the 4 to 60 km size range captured by Pan-STARRS1. Johnston (2019) lists fewer than 10 known binaries in this size range with separations greater than 10% of the primary's Hill radius, so discovering more wide binary asteroids is crucial for understanding the limits of binary stability and improving our knowledge of asteroid masses. We analyzed each image by: i) comparing the major…
Context: Occultations of stars by asteroids are an efficient method to study the properties of minor bodies, and can be exploited as tools to derive very precise asteroid astrometry relative to the target star. With the availability of stellar astrometry thanks to the ESA mission Gaia, the frequency of good predictions and the quality of the astrometry have been strongly enhanced. Aims: Our goal is to evaluate the astrometric performance of a systematic exploitation of stellar occultations, with a homogeneous data set and a given instrument setup. As a reference instrument, we adopt the exampl…
We have observed three near-Earth objects(NEOs), 2017VR12, Camillo, and Midas during the year 2018. The observations were made by the 1-m telescope of Yunnan Observatory over 2 nights. Their precise astrometric positions are derived from 989 CCD observations. The theoretical positions of asteroids are retrieved from the Jet Propulsion Laboratory (JPL) Horizons System and Institut de Mécanique Céleste et de Calcul des Éphémérides (IMCCE). The positions of three asteroids are measured with respect to the stars in Gaia DR2 star catalogue. For 2017 VR12, the mean (O-C) of right ascension and decli…
Detection and identification of asteroids with the 4-m ILMT
Institute of Astrophysics and Geophysics, Liège University（列日大学天体物理学与地球物理研究所）；Aryabhatta Research Institute of Observational Sciences（阿亚巴塔观测科学研究所）；National University of Uzbekistan（乌兹别克斯坦国立大学）；Ulugh Beg Astronomical Institute of the Uzbek Academy of Sciences（乌兹别克斯坦科学院乌鲁伯格天文研究所）；Mahatma Jyotiba Phule Rohilkhand University（马哈特玛·乔帝巴·普尔罗希尔坎德大学）；Department of Physics and Astronomy, The University of British Columbia（不列颠哥伦比亚大学物理与天文学系）；Outer Space Institute, The University of British Columbia（不列颠哥伦比亚大学外层空间研究所）；Kavli Institute for Astronomy and Astrophysics, Peking University（北京大学 Kavli 天体物理研究所）；University of Calcutta（加尔各答大学）
The GBOT group is in charge of the Ground Based Optical Tracking of the Gaia satellite. In concrete terms, since the launch of Gaia, our task is to take every night, using ground based medium-class telescopes, short sequences of $10$ or $20$ images of the Gaia satellite close to its meridian transit. For this purpose, we mainly use the VLT Survey Telescope and the Liverpool Telescope. In these images, taken close to the Sun's opposition - since Gaia is in L$_2$ - we observe many asteroids: between $30$ and $100$ asteroids every night, up to magnitude $22$. In order to extract the astrometric p…
Asteroids are classified as tiny and light objects in the solar system, however some of them possess orbiting moons. According to surveys, 15% of near-earth asteroids have moons. The Electrical Discharge effect provides a new model that describes the formation of single, binary, and triple asteroids influenced by solar magnetic activity. In further studies, collected data was drawn from the aggregation diagram of asteroids based on their average distance from the sun according to various databases, catalogs and spacecraft. The results show that, in areas where solar magnetic activity is high, …
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 Gaia spacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Gaia Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs. These asteroids have been already identified and have been numbered by the Minor Planet Center. Positions are provided for each Gaia observation at CCD level. As additional information, the apparent brightness of SSOs in the unfiltered G band is also provided for selected observations. We explain the processing of SSO data, and describe the criteria we …
We used binary octahedrons to investigate the dynamical behaviors of binary asteroid systems. The mutual potential of the binary polyhedron method is derived from the fourth order to the sixth order. The irregular shapes, relative orbits, attitude angles, as well as the angular velocities of the binary asteroid system are included in the model. We investigated the relative trajectory of the secondary relative to the primary, the total angular momentum and total energy of the system, the three-axis attitude angular velocity of the binary system, as well as the angular momentum of the two compon…
We have developed a new, fast method of estimating the orbital properties of a binary or triple system using as few as two epochs of astrometric data. FOBOS (Few Observation Binary Orbit Solver) uses a flat prior brute force Monte Carlo method to produce probability density functions of the likely orbital parameters. We test the code on fake observations and show that it can (fairly often) constrain the semi-major axis to within a factor of 2-3, and the inclination to within $\sim$20$^{\circ}$ from only two astrometric observations. We also show that the 68 and 95 per cent confidence intervals…
The evolution of rotation states of small asteroids is governed by the YORP effect, nonetheless some asteroids can stop their YORP evolution by attaining a stable equilibrium. The same is true for binary asteroids subjected to the BYORP effect. Here we discuss a new type of equilibrium that combines these two, which is possible in a singly synchronous binary system. This equilibrium occurs when the normal YORP, the tangential YORP and the binary YORP compensate each other, and tidal torques distribute the angular momentum between the components of the system and dissipate energy. Such a system…
Increasing observations of white dwarf atmospheric pollution and disrupting planetesimals is driving increased studies into the fate of exo-asteroids around post-main-sequence stars. Planetesimal populations in the Solar System which are most likely to survive the violent post-main-sequence evolution, such as the Kuiper Belt, display a large binary fraction with a propensity for near equal-mass components and provide a previously unexplored population of planetesimals which are likely to exist around white dwarfs. Here we simulate the dynamical evolution of equal-mass binary asteroid systems a…
We present the first public code for the calculation of the astrometric centroid shift occurring during microlensing events. The computation is based on the contour integration scheme and covers single and binary lensing of finite sources with arbitrary limb darkening profiles. This allows for general detailed investigations of the impact of finite source size in astrometric binary microlensing. The new code is embedded in version 3.0 of VBBinaryLensing, which offers a powerful computational tool for extensive studies of microlensing data from current surveys and future space missions.
Most close-in planetary satellites are in synchronous rotation, which is usually the stable end-point of tidal despinning. Saturn's moon Hyperion is a notable exception by having a chaotic rotation. Hyperion's dynamical state is a consequence of its high eccentricity and its highly prolate shape (Wisdom et al. 1984). As many binary asteroids also have elongated secondaries, chaotic rotation is expected for moons in eccentric binaries (Ćuk and Nesvorný, 2010), and a minority of asteroidal secondaries may be in that state (Pravec et al. 2016). The question of secondary rotation is also important…
Synchronous binary asteroids can experience libration about their tidally-locked equilibrium, which will result in energy dissipation. This is an important topic to the Asteroid Impact and Deflection Assessment, where excitation caused by the DART kinetic impact in the Didymos binary asteroid system may be reduced through dissipation before Hera arrives to survey the effects of the impact. We develop a numeric model for energy dissipation in binary asteroids to explore how different system configurations affect the rate of energy dissipation. We find tumbling within the synchronous state elimi…
